WO2017007240A1

WO2017007240A1 - Method and apparatus for measuring channel in mobile communication system

Info

Publication number: WO2017007240A1
Application number: PCT/KR2016/007332
Authority: WO
Inventors: 신철규; 김윤선; 노훈동; 곽영우; 오진영
Original assignee: 삼성전자 주식회사
Priority date: 2015-07-06
Filing date: 2016-07-06
Publication date: 2017-01-12
Also published as: EP3322110A1; US10644903B2; KR102480418B1; KR20180021201A; EP3322110A4; US20180205577A1

Abstract

The present disclosure relates to a 5G or pre-5G communication system for supporting a data transmission rate higher than a 4G communication system such as LTE. A method proposed in an embodiment of the present disclosure is a method for measuring a channel in a mobile communication system, comprising the steps of: receiving, from a base station, setting information for measuring a channel by using a reference signal; receiving the reference signal from the base station; measuring the channel by using the reference signal on the basis of the setting information; and transmitting information on the measured channel to the base station, wherein the setting information comprises at least one from among information related to time for measuring the channel and information related to the number of ports with respect to the reference signal.

Description

Method and apparatus for measuring channel in mobile communication system

The present disclosure relates to a method and apparatus for measuring a channel using a reference signal in a mobile communication system.

4G (4 ^th -Generation) to meet the traffic demand in the radio data communication system since the increase commercialized, efforts to develop improved 5G (5 ^th -Generation) communication system or a pre-5G communication system comprises . For this reason, a 5G communication system or a pre-5G communication system is called a after 4G network communication system or a post-LTE system.

In order to achieve high data rates, 5G communication systems are being considered for implementation in the ultra-high frequency (mmWave) band (eg, such as the 60 Gigabit (60 GHz) band). In 5G communication systems, beam forming, massive array multiple input / output (MID), and full dimensional MIMO (FD-MIMO) are used in 5G communication systems to reduce the path loss of radio waves and increase the transmission distance of radio waves in the ultra high frequency band. Array antenna, analog beam-forming, and large scale antenna techniques are discussed.

In addition, in order to improve the network of the system, 5G communication system has evolved small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense network Device to device communication (D2D), wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation Technology development is underway.

In addition, in 5G systems, advanced coding modulation (ACM), hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC), and advanced access technology, filter bank multi carrier (FBMC), and NOMA Non-orthogonal multiple access and sparse code multiple access are being developed.

Most of these techniques operate based on channel state information between an evolved node B (eNB) and a base station (eNB) and a user equipment (MS) and a mobile station (UE). It needs to be measured.

One embodiment of the present disclosure relates to a method and apparatus for measuring a channel using a reference signal in a mobile communication system.

In addition, another embodiment of the present disclosure relates to a method and an apparatus for measuring a channel using a reference signal based on configuration information for channel measurement for supporting a plurality of reference signal ports.

Method proposed in an embodiment of the present disclosure; A method of measuring a channel in a mobile communication system, the method comprising: receiving configuration information for channel measurement from a base station using a reference signal; Receiving the reference signal from the base station; Measuring a channel using the reference signal based on the configuration information; And transmitting information about the measured channel to the base station, wherein the configuration information includes at least one of information about time for measuring the channel and information about the number of ports for the reference signal. .

In addition, the device proposed in an embodiment of the present disclosure; An apparatus for measuring a channel in a mobile communication system, the apparatus comprising: a transceiver for transmitting and receiving data; And receiving, from a base station, configuration information for channel measurement using a reference signal, controlling the transceiver to receive the reference signal, measuring a channel using the reference signal based on the configuration information, and measuring the measurement. And a controller configured to control the transceiver to transmit the information on the determined channel to the base station, wherein the setting information includes at least one of information about time for measuring the channel and information about the number of ports for the reference signal. Include.

In addition, the method proposed in another embodiment of the present disclosure; A method of measuring a channel in a mobile communication system, the method comprising: transmitting setting information for channel measurement to a terminal using a reference signal; Transmitting the reference signal to the terminal; And receiving information on a channel measured using the reference signal from the terminal based on the configuration information, wherein the configuration information includes information about a time for measuring the channel and a port for the reference signal. It includes at least one of the information about the number of.

In addition, the device proposed in another embodiment of the present disclosure; An apparatus for measuring a channel in a mobile communication system, the apparatus comprising: a transceiver for transmitting and receiving data; And transmitting setting information for channel measurement to a terminal using a reference signal, transmitting the reference signal to the terminal, and receiving information on a channel measured using the reference signal from the terminal based on the setting information. And a control unit for controlling the transceiver to receive the information, wherein the setting information includes at least one of information about a time for measuring the channel and information about the number of ports for the reference signal.

Other aspects, benefits, and key features of the present disclosure will be apparent to those skilled in the art from the following detailed description, taken in conjunction with the accompanying drawings and disclosing preferred embodiments of the present disclosure.

Before proceeding with the following detailed description of the disclosure, it may be effective to set definitions for specific words and phrases used throughout this patent document: the terms "include" and " "Comprise" and its derivatives mean unlimited inclusion; The term “or” is inclusive and means “and / or”; The phrases “associated with” and “associated therewith” and their derivatives include, be included within, and interconnected with ( interconnect with, contain, be contained within, connect to or with, connect to or with Possibility to be communicable with, cooperate with, interleave, juxtapose, be proximate to, Is large or be bound to or with, have, have a property of, etc .; The term "controller" means any device, system, or portion thereof that controls at least one operation, wherein the device is hardware, firmware or software, or some combination of at least two of the hardware, firmware or software. It can be implemented in It should be noted that the functionality associated with any particular controller may be centralized or distributed, and may be local or remote. Definitions for specific words and phrases are provided throughout this patent document, and those skilled in the art will, in many instances, if not most of the cases, define such definitions as well as conventional and such definitions. It should be understood that this also applies to future uses of the syntax.

1 is a view briefly showing the configuration of the FD-MIMO system,

2 is a diagram illustrating an example of a radio resource that can be scheduled in downlink in an LTE / LTE-A system;

3 is a diagram illustrating an example of a signal transmitted from two eNBs to which IMR is applied;

4 to 8 are diagrams showing examples of feedback timing at which a terminal performs feedback;

9 to 11 are diagrams illustrating an example of a method for setting a measurement reset trigger through an Aperiodic CSI request according to embodiment 1-1 of the present disclosure;

12 illustrates an example of a measurement window according to a first embodiment of the present disclosure;

13 and 14 illustrate an example of a method for setting a measurement limiting technique according to embodiments 1-12 of the present disclosure;

15 is a diagram illustrating an example of a method of setting a measurement limiting technique according to embodiment 1-13 of the present disclosure;

16 illustrates a method for estimating a channel in a base station according to the first embodiment of the present disclosure;

17 is a diagram illustrating a method for estimating a channel in a terminal according to the first embodiment of the present disclosure;

18 is a diagram briefly illustrating an internal configuration of a base station for estimating a channel in an FD-MIMO system according to a first embodiment of the present disclosure;

19 is a diagram briefly illustrating an internal configuration of a terminal for estimating a channel in an FD-MIMO system according to the first embodiment of the present disclosure;

20 is a diagram illustrating a configuration of a communication system to which an embodiment of the present disclosure is applied;

FIG. 21 illustrates an example of supporting twelve CSI-RS ports using existing CSI-RS REs in a mobile communication system according to embodiment 2-1 of the present disclosure; FIG.

FIG. 22 is a diagram illustrating CSI-RS patterns for 12 port configured based on embodiment 2-1 of the present disclosure; FIG.

23 illustrates an example of supporting 16 CSI-RS ports using existing CSI-RS REs in a mobile communication system according to embodiment 2-2 of the present disclosure.

24A and 24B illustrate CSI-RS patterns for 16 ports based on embodiment 2-2 of the present disclosure;

FIG. 25 is a diagram illustrating an example of supporting 32 CSI-RS ports using existing CSI-RS REs in a mobile communication system according to embodiment 2-3 of the present disclosure; FIG.

FIG. 26 illustrates CSI-RS patterns for 32 port configured based on embodiment 2-3 of the present disclosure; FIG.

FIG. 27 illustrates an example of supporting twelve CSI-RS ports by additionally using REs used as PDSCHs as well as existing CSI-RS REs in a mobile communication system according to embodiments 2-4 of the present disclosure. ,

FIG. 28 illustrates CSI-RS patterns for 12 port configured based on embodiments 2-4 of the present disclosure; FIG.

FIG. 29 is a diagram illustrating an example of supporting 12 CSI-RS ports by additionally using REs used as PDSCHs as well as existing CSI-RS REs in a mobile communication system according to embodiment 2-5 of the present disclosure. ,

30 illustrates a CSI-RS pattern designed based on the first method in an embodiment 2-5 of the present disclosure;

FIG. 31 is a view illustrating a CSI-RS pattern in which a port position is changed in the CSI-RS pattern shown in FIG. 29;

FIG. 32 is a diagram illustrating an example of supporting twelve CSI-RS ports by additionally using not only existing CSI-RS REs but also REs used as PDSCHs in a mobile communication system according to embodiments 2-6 of the present disclosure; ,

33 is a view showing a CSI-RS pattern designed based on a first method in a second to sixth embodiments of the present disclosure;

FIG. 34 is a view illustrating a CSI-RS pattern having a changed port position in the CSI-RS pattern shown in FIG. 33;

FIG. 35 is a diagram illustrating an example of supporting 16 CSI-RS ports by additionally using not only existing CSI-RS REs but also REs used as PDSCHs in a mobile communication system according to embodiments 2-7 of the present disclosure. ,

36 illustrates a CSI-RS pattern designed based on a first method in Examples 2-7 of the present disclosure,

FIG. 37 is a view illustrating a CSI-RS pattern having a changed port position in the CSI-RS pattern shown in FIG. 35;

FIG. 38 illustrates an example of supporting 32 CSI-RS ports by additionally using REs used as PDSCHs as well as existing CSI-RS REs in a mobile communication system according to embodiments 2-8 of the present disclosure. ,

39 is a view showing a CSI-RS pattern designed based on a first method in an embodiment 2-8 of the present disclosure;

40 is a view illustrating CSI-RS patterns for 32 port configured based on embodiment 2-8 of the present disclosure;

FIG. 41 illustrates a configuration for supporting 16 CSI-RS ports in a PRB and supporting 16 CSI-RS ports by combining two PRBs in a mobile communication system according to embodiments 2-9 of the present disclosure; Drawing showing an example that supports all,

FIG. 42 is a view illustrating a CSI-RS pattern having a changed port position in the CSI-RS pattern shown in FIG. 41;

43 is a diagram illustrating a method for estimating a channel in a terminal according to a second embodiment of the present disclosure;

44 is a diagram illustrating a method for estimating a channel at a base station according to the second embodiment of the present disclosure;

45 is a diagram schematically illustrating an internal configuration of a terminal for estimating a channel according to the second embodiment of the present disclosure;

46 is a diagram schematically illustrating an internal configuration of a base station for estimating a channel in a second embodiment of the present disclosure.

Throughout the drawings, it should be noted that like reference numerals are used to depict the same or similar elements, features and structures.

DETAILED DESCRIPTION The following detailed description with reference to the accompanying drawings will assist in the comprehensive understanding of various embodiments of the disclosure, which are defined by the claims and their equivalents. The following detailed description includes various specific details for the purpose of understanding, but it will be regarded only as an example. Accordingly, those skilled in the art will recognize that various changes and modifications of the various embodiments described herein may be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and configurations may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are not to be limited in their literal meaning, but are merely used to enable a clear and consistent understanding of the present disclosure by the inventors. Therefore, to those skilled in the art, the following detailed description of various embodiments of the present disclosure is provided for illustrative purposes only and is intended to limit the present disclosure as defined by the appended claims and their equivalents. It should be clear that it is not provided for.

Also, it is to be understood that the singular forms "a" and "an", including the plural forms, include plural forms unless the context clearly dictates otherwise. Thus, as an example, a "component surface" includes one or more component representations.

In addition, terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present disclosure, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

Also, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. Singular expressions include plural expressions unless the context clearly indicates otherwise. As used herein, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Also, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Terms such as those defined in the commonly used dictionaries should be understood to have meanings consistent with those in the context of the related art.

First, a first embodiment of the present disclosure provides a terminal in a mobile communication system using a multiple access scheme using a multi-carrier such as orthogonal frequency division multiple access (OFDMA). It relates to a method of configuring and transmitting and receiving setting information for measuring the radio channel quality (channel quality).

Current mobile communication systems have evolved to provide high-speed, high-quality wireless packet data communication systems to provide data services and multimedia services, instead of providing voice-oriented services in the early days. To this end, standardization groups such as 3GPP (3rd generation partnership project), 3GPP2, and the Institute of Electrical and Electronics Engineers (IEEE) standardized the third generation evolutionary mobile communication system using the multiple access method using multiple carriers. Going on. Recently, various mobile communication standards such as LTE of 3GPP, ultra mobile broadband (UMB) of 3GPP2, and IEEE 802. 16m of IEEE have provided high-speed, high-quality wireless packet data transmission service based on multiple access method using multi-carrier. It was developed to support.

Existing third-generation evolutionary mobile communication systems such as LTE, UMB, and 802.11m are based on multi-carrier multiple access, and apply multiple antennas and beams in MIMO to improve transmission efficiency. It is characterized by using a variety of techniques such as forming, adaptive modulation and coding (AMC) and channel sensitive scheduling. Various techniques described above may be performed by concentrating or adjusting the amount of data transmitted from various antennas according to channel quality, and selectively transmitting data to a user having good channel quality. Improved transmission efficiency improves system capacity performance.

Most of these techniques operate based on channel state information between an evolved node B (eNB) and a base station (eNB) and a user equipment (MS) and a mobile station (UE). It is necessary to measure the channel status between the channels, and the channel status indication reference signal (CSI-RS) is used. The eNB refers to a downlink transmitting and uplink receiving apparatus located at a predetermined place, and one eNB performs transmission and reception for a plurality of cells. In a mobile communication system, a plurality of eNBs are geographically distributed, and each eNB performs transmission and reception for a plurality of cells.

Existing 3rd and 4th generation mobile communication systems such as LTE / LTE-A utilize MIMO technology that transmits using a plurality of transmit and receive antennas to increase data rate and system capacity. The MIMO technology spatially separates and transmits a plurality of information streams by utilizing a plurality of transmit / receive antennas. As described above, spatially separating and transmitting a plurality of information streams is called spatial multiplexing. In general, the number of information streams to which spatial multiplexing can be applied depends on the number of antennas of the transmitter and the receiver. In general, the number of information streams to which spatial multiplexing can be applied is called the rank of the transmission. MIMO technology, which is supported by the LTE / LTE-A Release 11 standard, supports spatial multiplexing for 8 transmit / receive antennas and supports up to 8 ranks. In addition, the FD-MIMO system under consideration in LTE-A Release 13 corresponds to the case where more than eight 32 or more transmission antennas are used by the evolution of the existing LTE / LTE-A MIMO technology.

1 briefly illustrates a configuration of an FD-MIMO system.

Referring to FIG. 1, a transmission device included in a base station transmits a radio signal to eight or more transmission antennas. The plurality of transmission antennas are arranged to maintain the minimum distance from each other as shown by reference numeral 110. Using the plurality of antenna sets 100, a base station transmits to a plurality of terminals using high order multi-user MIMO (high order multi user: MIMO). The higher order MU-MIMO is to transmit data by allocating spatially separated transmission beams to a plurality of terminals by using transmission antennas included in a plurality of base stations. Since the higher order MU-MIMO is made using the same time and frequency resources, there is an advantage that can significantly improve the performance of the system.

In general, MIMO is a single user MIMO (SU-MIMO) for transmitting a plurality of spatially multiplexed data streams to one UE and an MU for transmitting a plurality of spatially multiplexed data streams simultaneously to a plurality of UEs. It is classified as MIMO. In the SU-MIMO, a plurality of spatially multiplexed data streams are transmitted to one terminal, but in MU-MIMO, a plurality of spatially multiplexed data streams are transmitted to a plurality of terminals. In the MU-MIMO, the base station transmits a plurality of data streams, and each terminal receives one or more data streams among the plurality of data streams transmitted by the base station. Such MU-MIMO is particularly useful when the number of transmission antennas of the base station is larger than that of the terminal. In the case of SU-MIMO, the maximum number of spatially multiplexed data streams is limited by min (N _Tx , N _Rx ). Where N _Tx is the number of transmission antennas of the base station and N _Rx is the number of reception antennas of the terminal. On the other hand, in MU-MIMO, the maximum number of spatially multiplexed data streams is limited by min (N _Tx , N _MS, N _Rx ). Here, N _MS corresponds to the number of terminals.

It is expected that higher order MU-MIMO transmission will occur more frequently in the FD-MIMO system. Therefore, in order to effectively implement the FD-MIMO system, the terminal must accurately measure the channel situation and the magnitude of interference and transmit the effective channel state information to the base station using the same. The base station receiving the channel state information uses this to perform SU-MIMO on a specific terminal in connection with downlink transmission, whether to perform MU-MIMO to a plurality of terminals, or at what data transmission rate, And which precoding to apply.

2 shows radio resources that can be scheduled in downlink in an LTE / LTE-A system.

Referring to FIG. 2, a radio resource that can be scheduled in downlink in an LTE / LTE-A system includes one subframe on a time axis, and one resource block (RB) on a frequency axis. Is done. Such radio resources consist of 12 subcarriers in the frequency domain and 14 OFDM symbols in the time domain to have a total of 168 unique frequencies and time locations. In LTE / LTE-A, each natural frequency and time position of FIG. 2 is referred to as a resource element (RE).

In the radio resource illustrated in FIG. 2, a plurality of different types of signals may be transmitted as follows.

1. Cell specific RS (CRS): A reference signal periodically transmitted for all UEs belonging to one cell and can be commonly used by a plurality of UEs.

2. Demodulation reference signal (DMRS): A reference signal transmitted for a specific terminal and is transmitted only when data is transmitted to the corresponding terminal. DMRS may consist of a total of eight DMRS ports. In LTE / LTE-A, ports 7 through 14 correspond to DMRS ports, and each of the ports interferes with each other using code division multiplexing (CDM) or frequency division multiplexing (FDM). Maintain orthogonality to avoid

3. Physical downlink shared channel (PDSCH): A data channel transmitted in downlink, which is used by a base station to transmit traffic to a terminal, and a reference signal is transmitted in the data region of FIG. Is sent using non-RE

4. CSI-RS: Reference signal transmitted for UEs belonging to one cell and used to measure a channel state. A plurality of CSI-RSs may be transmitted in one cell. In the LTE-A system, one CSI-RS may correspond to one, two, four, or eight antenna ports.

5. Zero power CSI-RS (zero power CSI-RS): This means that no actual signal is transmitted at the position where the CSI-RS is transmitted.

6. Interference measurement resource (IMR): Corresponds to the location where the CSI-RS is transmitted, and in Fig. 2, one or more of A, B, C, D, E, F, G, H, I, J. Can be set to IMR. The UE assumes that all signals received from REs configured as IMR are interference and performs interferometry.

7. Other Control Channels: Other control channels include physical hybrid-automatic request for repeatitiom indicator channel (PHICH), physical control format indicator channel (PCFICH) and physical downlink. Physical downlink control channel (PDCCH). The terminal is used to provide control information necessary for receiving the PDSCH or transmit a normal response / negative response (ACK / NACK) for operating HARQ for uplink data transmission.

In addition to the signal, in the LTE-A system, muting may be set so that CSI-RSs transmitted from other base stations can be received without interference from terminals of corresponding cells. The muting may be applied at a location where the CSI-RS can be transmitted, and in general, the terminal receives a traffic signal by skipping a corresponding radio resource. Muting in LTE-A system is another term also called zero-power CSI-RS. This is because muting is applied equally to the position of the CSI-RS due to the nature of muting, and transmission power is not transmitted.

In FIG. 2, the CSI-RS may be transmitted using a part of positions indicated as A, B, C, D, E, E, F, G, H, I, J according to the number of antennas transmitting the CSI-RS. have. Muting may also be applied to some of the positions marked A, B, C, D, E, E, F, G, H, I, J. In particular, the CSI-RS may be transmitted to 2, 4, and 8 REs according to the number of antenna ports to transmit. In the case of two antenna ports, the CSI-RS is transmitted in half of a specific pattern in FIG. 2, and in the case of four antenna ports, the CSI-RS is transmitted in the entirety of a specific pattern. -RS is sent Muting, on the other hand, always consists of one pattern unit. That is, the muting may be applied to a plurality of patterns, but may not be applied to only a part of one pattern when the position does not overlap with the CSI-RS. However, it can be applied only to a part of one pattern only when the position of the CSI-RS and the position of the muting overlap.

Also, A, B, C, D, E, F, G, H, I, and J of FIG. 2 may be set to IMR, respectively. When IMR is set for a specific UE, the UE assumes that signals received from REs belonging to the configured IMR are interference signals. The purpose of the IMR is to allow the terminal to measure the strength of the interference. That is, the terminal determines the strength of the interference by measuring the strength of the signal received from the REs belonging to the IMR configured for the UE.

3 shows signals transmitted from two eNBs to which IMR is applied. Hereinafter, the operation principle of the IMR will be described with reference to FIG. 3.

Referring to FIG. 3, eNB A configures IMR C for a UE located in cell A. FIG. In addition, eNB B sets the IMR J for the UE located in the cell B. That is, the UEs located in the cell A receive the PDSCH transmitted from the eNB A. For this purpose, the UEs must notify the channel state information of the eNB A. In order to generate the channel state information, the terminal should be able to measure signal energy versus interference and noise intensity (Es / (Io + No)) of the channel. The purpose of the IMR is to allow the UE to measure interference and noise strength. In FIG. 3, when eNB A and eNB B simultaneously transmit, interference occurs with each other. That is, the signal transmitted from the eNB B acts as an interference to the terminal receiving the signal from the eNB A. In addition, the signal transmitted from the eNB A acts as an interference to the terminal receiving the signal from the eNB B.

In FIG. 3, eNB A sets IMR C to the UE so that the UE located in the cell A measures interference generated by the eNB B. FIG. In addition, eNB A does not transmit a signal at the position of IMR C. As a result, the signal received by the UE in IMR C is a signal transmitted from eNB B as shown by

reference numerals

300 and 310. That is, the terminal receives only the signal transmitted from the eNB B in the IMR C, and can measure the reception strength of the signal to determine the strength of the interference generated in the eNB B. Similarly, eNB B sets the IMR J to the UE so that the UE located in the cell B measures the interference generated by eNB A. In addition, eNB B does not transmit a signal at the position of IMR J.

When using IMR as shown in FIG. 3, it is possible to effectively measure the strength of interference generated at another eNB or transmission point. That is, in the multi-cell mobile communication system or distributed antenna system in which a plurality of cells coexist, the IMR may be used to effectively measure the strength of interference generated in neighboring cells or the interference generated in neighboring transmission points. IMR can also be used to measure the strength of MU-MIMO interference.

In a cellular system, a base station must transmit a reference signal to a terminal in order to measure a downlink channel state. In the LTE-A system of 3GPP, the terminal measures the channel state between the base station and itself using a CRS or CSI-RS transmitted by the base station. The channel state basically needs to consider several factors, including the amount of interference in the downlink. The amount of interference in the downlink includes an interference signal generated by an antenna belonging to an adjacent base station, thermal noise, and the like, and is important for a terminal to determine a downlink channel condition. For example, when a transmitting antenna transmits a signal from one base station to one terminal, the terminal receives energy per symbol and a corresponding symbol that can be received in downlink using a reference signal received from the base station. At the same time, the amount of interference to be received must be determined and the signal energy to interference intensity (Es / Io) must be determined. The determined Es / Io is converted into a data transmission rate or a corresponding value, and notified to the base station in the form of a channel quality indicator (CQI), so that the base station transmits to the terminal at a certain data transmission rate in downlink. Allows you to determine whether to perform.

In case of the LTE-A system, the terminal feeds back information on the channel state of the downlink to the base station so that the terminal can utilize the downlink scheduling. That is, the terminal measures the reference signal transmitted by the base station in downlink and feeds back the extracted information to the base station in the form defined in the LTE / LTE-A standard. As channel state information (CSI) fed back by the terminal in LTE / LTE-A, a rank indicator (RI), a precoder matrix indicator (PMI), and a channel quality indicator (channel quality indicator) : CQI).

The RI is the number of spatial layers that the UE can receive in the current channel state, the PMI is an indicator of a precoding matrix that the UE prefers in the current channel state, and the CQI is the UE's current The maximum data rate that can be received in the channel state. Here, the CQI may be replaced with a signal to interference plus noise ratio (SINR), a maximum error correction code rate and modulation scheme, and data efficiency per frequency, which may be utilized similarly to the maximum data rate. Can be.

In the current LTE / LTE-A standard, the RI, PMI and CQI are all defined as SU-CSI which assumes and feeds back SU-MIMO transmission. The RI, PMI and CQI are associated with each other and have meaning. As an example, the precoding matrix supported by LTE / LTE-A is defined differently for each rank. Therefore, the PMI value when RI has a value of 1 and the PMI value when RI has a value of 2 are interpreted differently. Also, when the UE determines the CQI, it is assumed that the rank value and the PMI value informed by the UE of the BS are applied by the BS. That is, when the terminal informs the base station of RI_X, PMI_Y and CQI_Z, it means that the terminal can receive a data rate corresponding to CQI_Z when the rank is RI_X and the precoding is PMI_Y. As such, the UE assumes a transmission method to the base station when calculating the CQI, so that the optimized performance can be obtained when the actual transmission is performed using the transmission method.

In LTE / LTE-A, periodic feedback of a UE is set to one of the following feedback modes (feedback mode or reporting mode) according to what information is included:

Feedback Mode 1-0: RI, Wideband CQI (wCQI)

2. Feedback Mode 1-1: RI, wCQI, PMI

3. Feedback Mode 2-0: RI, wCQI, Subband CQI (sCQI)

4. Feedback Mode 2-1: RI, wCQI, sCQI, PMI

The feedback timing of each information for the four feedback modes is determined by values of N _pd , N _{OFFSET, CQI} , M _RI , and N _{OFFSET, RI,} etc., which are transmitted as a higher layer signal. The terminal performs feedback to the base station at the feedback timing shown in FIGS. 4 to 8. 4 to 8 illustrate feedback timings at which the terminal performs feedback.

In feedback mode 1-0, the transmission period of wCQI is N _pd The feedback timing is determined using subframe offset values of N _{OFFSET and CQI} . In addition, the transmission period of RI is

Is a subframe and the offset is

to be.

4 is a diagram illustrating feedback timings of RI and wCQI in the case of N _pd = 2, M _RI = 2, N _{OFFSET, CQI} = 1, and N _{OFFSET, RI} = -1. In FIG. 4, each timing represents a subframe index.

Feedback mode 1-1 has the same feedback timing as mode 1-0, except that wCQI and PMI are transmitted together at the wCQI transmission timing for one, two antenna ports, or some four antenna port situations.

In feedback mode 2-0, the feedback period for sCQI is N _pd subframe, and the offset value is N _{OFFSET, CQI} . And the feedback period for wCQI

It is a subframe, and the offset value is N _{OFFSET and CQI} like the offset value of sCQI. here

K is transmitted as an upper signal, and J is a value determined according to the system bandwidth. For example, the J value for a 10 MHz system is defined as 3. Accordingly, wCQI is transmitted in turn once per H sCQI transmissions. And the cycle of RI

Is a subframe and the offset is

to be.

5 is

RI, sCQI, wCQI feedback timing for the case of. Feedback mode 2-1 has the same feedback timing as mode 2-0, except that PMI is transmitted together in wCQI transmission timing for one, two antenna ports, or some four antenna port situations.

The above-described feedback timing is for a part of the case where the number of CSI-RS antenna ports is one, two, or four, and the terminal has been allocated CSI-RS for another four antenna ports or eight antenna ports. In this case, unlike the feedback timing, two types of PMI information are fed back. In case that the UE is allocated CSI-RS having another 4 antenna ports or some 8 antenna ports, feedback mode 1-1 is divided into two submodes, and RI is the first submode. The PMI information is transmitted along with the second PMI information along with the wCQI. Here, the period and offset of feedback for wCQI and second PMI are defined as N _pd , N _{OFFSET, CQI} , and the feedback period and offset values for RI and first PMI information are respectively.

Wow

Is defined as When both the first PMI ( i ₁ ) and the second PMI ( i ₂ ) are reported from the terminal to the base station, the terminal and the base station correspond to the combination of the corresponding first PMI and the second PMI in a set of precoding matrices shared by each other. The precoding matrix W ( i ₁ , i ₂ ) to be identified as the preferred precoding matrix of the terminal. In another interpretation, if the precoding matrix corresponding to the first PMI is called W ₁ and the precoding matrix corresponding to the second PMI is referred to as W ₂ , the UE and the base station have a W ₁ W in which the UE's preferred precoding matrix is a product of two matrices. Share the information that the decision by _two.

When the feedback mode for the eight CSI-RS antenna ports is 2-1, precoding type indicator (PTI) information is added to the feedback information. At this time, the PTI is fed back with the RI and the period is

Is a subframe and the offset is

Is defined as

Specifically, when the PTI is 0, the first PMI, the second PMI, and the wCQI are all fed back. At this time, wCQI and the second PMI are transmitted together at the same timing, the period is N _pd and the offset is given as N _{OFFSET, CQI} . The first PMI cycle

Offset is N _{OFFSET, CQI} . Where H 'is transmitted as a higher signal.

On the other hand, if the PTI is 1, wCQI is transmitted with the wideband second PMI and sCQI is fed back with the narrowband second PMI at a separate timing. In this case, when the first PMI is not transmitted and the PTI is 0, the second PMI and the CQI are calculated after assuming the first PMI reported last. The period and offset of PTI and RI are the same as when PTI is zero. period of sCQI is N _pd It is defined as a subframe, and the offset is defined as N _{OFFSET, CQI} . wCQI and the second PMI

It is fed back with the period of N _{offset and} offset of _CQI , and H is defined as if the number of CSI-RS antenna ports is two.

6 and 7

Is a diagram showing feedback timing when PTI = 0 and PTI = 1, respectively.

LTE / LTE-A supports aperiodic feedback as well as periodic feedback of the terminal. When the base station wants to obtain aperiodic feedback information of a specific terminal, the base station performs specific aperiodic feedback of the aperiodic feedback indicator included in downlink control information (DCI) for uplink data scheduling of the terminal. Set to perform uplink data scheduling of the corresponding terminal. When the terminal receives an indicator configured to perform aperiodic feedback in the nth subframe, the terminal performs uplink transmission by including aperiodic feedback information in data transmission in the n + kth subframe. Where k is a parameter defined in the 3GPP LTE Release 11 standard and is 4 in frequency division duplexing (FDD) and is defined in Table 1 in time division duplexing (TDD). Table 1 below shows k values for each subframe number n in a TDD UL / DL configuration.

TABLE 1

When the aperiodic feedback is set, the feedback information includes RI, PMI, and CQI as in the case of periodic feedback, and the RI and PMI may not be fed back according to the feedback setting. The CQI may include both wCQI and sCQI, or may include only wCQI information.

Recently, a method of transmitting a beam optimized for a UE to a CSI-RS resource in a FD-MIMO system has been discussed. Since the FD-MIMO system is capable of beamforming in a vertical and horizontal direction according to the position of the terminal, when the beamforming is transmitted through the CSI-RS resource, the FD-MIMO system measures the channel based on the beamformed signal to the terminal and transmits information on the information. Feedback is available to maximize the gain of the FD-MIMO system. However, unlike the conventional method of not beamforming the CSI-RS, an issue related to channel measurement occurs in the case of the beamformed CSI-RS. Issues related to channel measurement arise because beams take different time and frequency resources. The current standard is not to give a measurement restriction when the terminal determines the CQI. Accordingly, the terminal acquires channel information through time averaging in time when performing channel measurement. That is, the terminal performs channel measurement using the CSI-RS which comes down periodically and averages this to determine the channel state. However, if the channel measurement method is performed on a beamformed CSI-RS to which a beam that changes in time is applied, the channel state may be incorrectly identified. In addition, the CSI set up based on this may cause an incorrectly determined problem.

As described above, since the FD-MIMO system can be beamformed in the vertical and horizontal directions according to the position of the terminal, when the FD-MIMO system transmits the beamforming to the CSI-RS resource, By measuring and feeding back information about this, the gain of the FD-MIMO system can be maximized. However, since beamforming may vary according to time-frequency resources, when performing channel measurement on a beamformed CSI-RS, it may be difficult to obtain accurate channel information without limiting time averaging.

Here, the measurement limit may be used for obtaining channel information and obtaining interference information.

First, when used to obtain channel information, the measurement limit may be defined as follows.

If measurement limits for channel estimation are performed for a given CSI process, the channel used for CSI generation includes M non zero power (NZP) CSI- including CSI reference resources. It can be estimated using up to RS subframes.

Channel measurements are derived from the NZP CSI-RS.

-> M value is configured correctly to the terminal or the terminal can select from a value between 1 and Z _M. Next, when used to obtain interference information, the measurement limit may be defined as follows.

If measurement constraints on channel estimation are performed for a given CSI process with CSI-IM (s), the interference used for CSI generation can be estimated using up to N CSI-IM subframes, including CSI interference resources. have.

Interference measurements are derived from the CSI-IM.

-> N value is configured correctly to the terminal or the terminal can select from a value between 1 and Z _N.

In the first embodiment of the present disclosure, in order to solve this problem, the base station delivers the configuration information for channel measurement to the terminal to look at the methods for performing the channel measurement based on the configuration information received from the base station. As described above, a method of measurement reset is proposed as a method for limiting measurement to time averaging for a reference signal when performing channel measurement. The measurement reset means that the terminal initializes the result of the channel estimation at a predetermined time point.

In a first embodiment of the present disclosure, as a method of configuring configuration information for channel measurement by a base station, a measurement reset trigger method and a measurement window method are proposed.

The purpose of the base station to configure the configuration information for the channel measurement is to allow the terminal to accurately measure the channel state to feed back the CSI to the base station. Therefore, the term may be modified into terms suitable for the user's intention. In addition, the proposed method can be used not only for channel measurement for beamformed CSI-RS but also for channel measurement for IMR. Although all embodiments are described based on the CSI-RS, the CSI-RS may be replaced with the CSI-IM, and may be used for the interference measurement for the IMR. More specifically, in the 3GPP RAN1 # 82 conference, the non-precoded CSI-RS for the CSI-RS is beamformed as Class A, and the CSI-RS is named as Class B. In addition, in the 3GPP RAN1 # 82b conference, it was decided to support only measurement limitations for interference using CSI-IM in Class A, and to use CSI-RS for CSI-RS for class B. It was decided to support all measurement limits for interference.

Hereinafter, the measurement reset trigger method and the measurement window method will be described in detail as a method for configuring the configuration information for channel measurement by the base station.

First, a method of configuring configuration information for channel measurement based on a measurement reset trigger will be described.

8 illustrates an example of a measurement reset trigger according to a first embodiment of the present disclosure. 8 shows that the CSI-RS is periodically transmitted. Referring to FIG. 8, the base station sets a measurement reset trigger at a specific time point and transmits the measurement reset trigger to the terminal. Then, the terminal initializes the channel estimation value for the CSI-RS when receiving the measurement reset trigger from the base station. In FIG. 8, CSI-RSs are displayed in different shapes to distinguish CSI-RSs used for channel estimation due to initialization. In the first embodiment of the present disclosure, the measurement reset trigger causes the base station to initialize the channel estimation value for the CSI-RS dynamically through L1 signaling. The terms of the measurement reset are defined according to the user's intention, CSI reset, CSI reference resource restriction, valid CSI-RS restriction, DL subframe restriction, Alternatively, terms such as a beamforming (BF) change indicator may be substituted.

Hereinafter, in each embodiment of the first embodiment of the present disclosure, the method for initializing the channel estimation value for the CSI-RS through a measurement reset trigger includes the aperiodic CSI request method and the DCI signaling. It demonstrates using a method.

Hereinafter, a method of setting a measurement reset trigger based on an Aperiodic CSI request according to embodiment 1-1 of the present disclosure will be described with reference to FIG. 9. The base station may interpret setting the Aperiodic CSI request as setting the measurement reset trigger without using separate LI signaling to set the measurement reset trigger.

9 to 11 illustrate an example of a method for setting a measurement reset trigger through an Aperiodic CSI request according to embodiment 1-1 of the present disclosure.

In FIG. 9, the CSI-RS is periodically transmitted, and it is assumed that the base station decides to change the beam to Beamforming 2 in the next subframe while transmitting the CSI-RS by applying Beamforming 1. At this time, the base station performs an operation of setting an Aperiodic CSI request to set a measurement reset trigger.

As shown in FIG. 9, the timing for setting the Aperiodic CSI request is set in the base station. 9 illustrates three timings at which the base station sets an Aperiodic CSI request. If the base station uses Aperiodic CSI request timing-1, since the UE did not receive the CSI-RS to which Beamforming 2 was applied at this point, in order to perform channel estimation on the CSI-RS to which Beamforming 2 (903) was applied, the following CSI- There is a problem that the CSI report is delayed because it has to wait until receiving the RS. . If the base station uses Aperiodic CSI request timing-3, the UE may not perform measurement reset on the CSI-RS to which Beamforming 2 has already been applied. If the base station uses Aperiodic CSI request timing-2, the above problem can be solved. However, if a large number of users are scheduled at the same time in Aperiodic CSI request timing-2, scheduling restrictions may occur in the PUSCH.

In order to solve this problem, the base station may set a measurement reset trigger to always perform a measurement reset in the case of Aperiodic CSI request as shown in FIG.

Alternatively, the base station may configure a measurement reset trigger by additionally setting reset ON / OFF by adding one bit to the uplink DCI. For example, as shown in FIG. 11, the UE initializes channel estimation when an added bit based on an uplink DCI is set to reset ON, and Aperiodic CSI by time-arranging channel information since previously initialized when set to reset OFF. Report can be performed. Here, Uplink DCI means

DCI format

0 or 4.

Unlike the method in which the Aperiodic CSI report is always performed for one CSI-RS in FIG. 10, in FIG. 11, there is an advantage in that the accuracy can be increased by timing arranging the CSI-RS for the fixed beam.

The method of embodiment 1-1 may be applied to periodic CSI report as well as Aperiodic CSI report. As in the proposed method, when the UE performs the Aperiodic CSI report, the UE may perform channel estimation initialization for the CSI-RS periodically transmitted through the Aperiodic CSI request. In addition, even when performing a periodic CSI report, the UE may perform channel estimation initialization for the CSI-RS through an Aperiodic CSI request. The operation of performing the Aperiodic CSI report and the Periodic CSI report will be described in detail with reference to Examples 1-9 below. Next, a method of setting a reset range when setting a measurement reset trigger through an Aperiodic CSI request as in the first-first embodiment of the present disclosure will be described.

Table 2 below shows a CSI request field for a PDCCH / EPDCCH having an uplink DCI format in a UE specific search space. When Aperiodic CSI request is set because the CSI request field is set to '01', '10', or '11' as shown in <Table 2>, up to 4 CSI processes connected to it are set to '01' Up to 5 and up to 5 if the value is set to '10' or '11'.

TABLE 2

Therefore, in case of setting measurement reset trigger through Aperiodic CSI request, the range of reset may be set as follows.

Alt-1: Performs a measurement reset for all configured CSI processes.

Alt-2: Defines whether to perform measurement reset in RRC and performs measurement reset for the corresponding CSI-RS / CSI-IM or CSI process.

Alt-3: Defines whether to perform measurement reset in Uplink DCI and performs measurement reset for the corresponding CSI-RS / CSI-IM or CSI process.

Alt-1 has the advantage that additional higher layer signaling or L1 signaling is not required, but there is a problem that measurement reset may be performed on the non-beamformed CSI-RS. In addition, in case of Alt-3, it is necessary to determine whether to perform measurement reset through L1 signaling, which may cause an issue of signaling overhead. In addition, in the case of Alt-2, as a method of determining whether to perform a measurement reset by using higher layer signaling, there is a free advantage in signaling overhead compared to Alt-3.

Determining whether to perform a measurement reset using Alt-3 among the above methods may be set in the following manner.

-Define measurement reset turn ON / OFF in CSI-process field.

-Define the measurement reset turn ON / OFF in the CSI-RS-Config field.

-Define the measurement reset turn ON / OFF in the CSI-RS-Config field and the CSI-IM-Config field.

Defining whether to perform measurement reset on the higher layer signaling may be displayed as shown in Table 3 below. However, the method of defining whether to perform measurement reset in higher layer signaling is not limited to the method of <Table 3>. If the execution of measurement reset is defined in the CSI process field, the CSI-RS-Reset function and the CSI-IM-Reset function may be defined in the CSI process field. Or only one of them may be defined.

TABLE 3

If the execution of the measurement reset is defined only in the CSI-RS-Config field, only the CSI-RS-Reset function is included in <Table 3>. In this case, the execution of the CSI-IM measurement reset may not be defined. Alternatively, whether to perform the CSI-IM measurement reset may be determined according to the CSI-RS-Reset. If the measurement reset is performed using both the CSI-RS-Config field and the CSI-IM-Config field, the CSI-RS-Reset function and the CSI-IM-Reset function are shown in Table 3, respectively. Can be defined in Config field and CSI-IM-Config field.

<1-2 Example: How to set up measurement reset trigger based on uplink DCI>

Hereinafter, a method of setting a measurement reset trigger based on the uplink DCI according to the embodiment 1-2 of the present disclosure will be described. Here, Uplink DCI means

DCI format

0 or 4. The method of the embodiment 1-2 further defines one bit in the uplink DCI and sets measurement reset trigger ON / OFF using the one bit information. In the first-first embodiment, since the measurement reset trigger is set based on the Aperiodic CSI request, the Aperiodic CSI report is always performed when the measurement reset trigger is set. However, in the embodiment 1-2 of the present disclosure, the measurement reset trigger may be set using one bit defined in the uplink DCI. In the case of setting the measurement reset trigger through the uplink DCI as in the embodiment 1-2 of the present disclosure, a method such as Alt-1, Alt-2, and Alt-3 described above may be used for setting the range of the reset. .

<1-3 Example: Transmission power control (TPC) based on DCI measurement reset trigger>

Hereinafter, a method of setting a measurement reset trigger based on the TPC DCI according to the embodiment 1-3 of the present disclosure will be described. Here, TPC DCI means DCI format 3 or 3a. For the method of the embodiment 1-3 of the present disclosure, refer to the TPC command field defined for the TPC (TPC command field, 3GPP TS 36.213 Table 5. 1. 1-2, 5. 1. 1. 1-3) Instead of), the measurement reset field is defined as shown in Tables 4 and 5 below. In addition, by defining a new Radio Network Temporary Identifier (RNTI), DCI format 3 or 3a can be used for TPC and also used for measurement reset trigger.

TABLE 4

TABLE 5

Table 4 shows an example of defining a measurement reset field in DCI format 3. The two available options are as follows.

First, option-1 is a method of setting a CSI-RS process to perform a measurement reset while setting a measurement reset trigger. Option-2 is a method of setting a measurement reset trigger in consideration of carrier aggregation (CA) and setting a CSI-RS process set for performing a measurement reset. When the option-2 is used, the method of setting the range of the reset may be used, such as Alt-1, Alt-2, and Alt-3. Table 5 shows a case where a measurement reset field is defined in DCI format 3a. Even in this case, methods such as Alt-1, Alt-2, and Alt-3 in the 1-2 embodiment may be used to set the reset range.

Next, the base station configures configuration information for channel measurement based on the measurement window.

12 illustrates an example of a measurement window according to a first embodiment of the present disclosure.

12 shows that CSI-RSs are periodically transmitted, and an example in which measurement windows are set for five CSI-RSs is shown. Here, the measurement window refers to a section that can be time-averaged during channel estimation using the CSI-RS. It also initializes the channel estimates for the CSI-RS at the beginning of every measurement window. The measurement window may be defined as a time interval or as a number of transmitted CSI-RSs. For example, in FIG. 12, assuming that the CSI-RSs are transmitted every 5 msec, the measurement window may be defined as 20 msec or 5 as the number of transmitted CSI-RSs.

Table 6 shows the case where the measurement window periodicity is defined as a time interval and the number of transmitted CSI-RSs (

It shows an example of the case defined by). If the measurement window is defined as the number of transmitted CSI-RSs

If = 1

= 1 and

For the measurement window interval

CSI-RS Cycle

from It can be calculated as follows.

Table 6-1 shows a subframe configuration method for the measurement window.

In Table 6 and Table 6-1, the integer X may be interpreted as not performing a measurement reset. And X _k in <Table 6-1> Represents the measurement window period. More specifically, in Table 6-2, examples of <Table 6-1> are shown.

TABLE 6

TABLE 6-1

TABLE 6-2

In the first embodiment of the present disclosure, the measurement window is transmitted from the base station to the terminal through higher layer signaling to initialize the channel estimation value for the CSI-RS within a predetermined period. In the first embodiment of the present disclosure, the measurement window may be operated in various measurement window configurations as shown in Table 6-1, or may be operated in one fixed measurement window. For example, when operating in various measurement window configurations, the base station determines the number of measurement windows to operate and signals the INTEGER (0..X) value. When the base station operates in various measurement window configurations, the base station may set a size of a measurement window suitable for a situation, but the terminal implementation may be complicated.

On the other hand, when operating a fixed measurement window, the base station determines a specific measurement window size and signals the INTEGER (A, X) value. In this case, the A value may be set to a fixed measurement window period value, and the measurement window subframe offset may be set to a value between 1 and A. For example, if A is set to 1, the channel estimation value for the CSI-RS is initialized for every CSI-RS reception, and if X is configured with higher layer signaling, the channel estimation value for the CSI-RS is not initialized. Do not. In addition, in consideration of periodic CSI reporting, the measurement window value may be set in consideration of the period in which the RI is transmitted. Detailed operations thereof will be described in detail with reference to Examples 1-9 of the present disclosure. As such, when the measurement window size is fixedly operated, the terminal implementation may be simpler than when operating the measurement window configuration.

In the first embodiment of the present disclosure, when operating in various measurement window configurations, it is described as INTEGER (0. .X), and when it is operated by one fixed measurement window, it will be described as INTEGER (A, X). .

The measurement window subframe offset is determined using Table 6-1 above, which is operated with various measurement window configurations, and the measurement window subframe offset is set to INTEGER (0..A) when operated with one fixed measurement window. Can be configured. In addition, the terms of the measurement window are defined as CSI reset window, CSI reference resource restriction window, valid CSI-RS restriction window, DP subframe proposal window ( It may be replaced with terms such as a DL subframe restriction window, or a BF change window.

In the following embodiments 1-4, 1-5, and 1-6 of the present disclosure, a method of configuring a measurement window value and a measurement window subframe configuration using higher layer signaling is described. And, it will be described through the CSI report configuration. In addition, in the first to eleventh embodiments of the present disclosure, a method of setting a measurement window value and a measurement window subframe configuration without additional higher layer signaling will be described.

A method of setting a measurement window based on the CSI-RS configuration according to the embodiment 1-4 of the present disclosure will be described with reference to Table 7 below.

Table 7 below shows a CSI-RS configuration field. Embodiment 1-4 of the present disclosure is a case of setting a measurement window in the CSI-RS-Config field. Specifically, in the first to fourth embodiments of the present disclosure, the following fields may be added for the CSI-RS and the CSI-IM.

-CSI-RS-MeasurementConfig INTEGER (0. .X) or INTEGER (A, X)

-CSI-IM-MeasurementConfig INTEGER (0. .X) or INTEGER (A, X)

Additional setting: CSI-RS-Measurementoffset INTEGER (1.. A) when operated with one fixed measurement window

The INTEGER value set here is shown in Table 6, and X indicates that the measurement reset is not performed.

TABLE 7

A method of setting a measurement window based on the CSI process according to the embodiment 1-5 of the present disclosure will be described with reference to Table 8 below.

Table 8 below shows a CSI-Process field. Embodiment 1-5 of the present disclosure is a case of setting a measurement window in the CSI-Process field. In detail, in the embodiments 1-5 of the present disclosure, the following fields may be added for the CSI-RS and the CSI-IM.

-CSI-RS-MeasurementConfig INTEGER (0. .X) or INTEGER (A, X)

-CSI-IM-MeasurementConfig INTEGER (0. .X) or INTEGER (A, X)

The INTEGER value set here is referred to in Table 6, and X indicates that the measurement reset is not performed.

TABLE 8

<1-6 Example: How to set up measurement window based on CSI report configuration>

A method of setting a measurement window based on the CSI report configuration according to the embodiment 1-6 of the present disclosure will be described with reference to Table 9 below.

Table 9 shows a CSI-Process field and Table 10 shows a CQI-ReportPeriodic field. Embodiments 1-6 of the present disclosure are cases where a measurement window is set in a CSI-Process field or a CQI-ReportPeriodic field. In detail, in the first to sixth embodiments of the present disclosure, the following fields may be added for the CSI-RS and the CSI-IM.

-CSI-RS-MeasurementConfig INTEGER (0. .X) or INTEGER (A, X)

-CSI-IM-MeasurementConfig INTEGER (0. .X) or INTEGER (A, X)

TABLE 9

TABLE 10

If the measurement window is set in the CQI-ReportPeriodic field and the Aperiodic CSI report is operating, the terminal may measure the channel with reference to the measurement window value set in the CQI-ReportPeriodic field.

Next, when the terminal is set to CSI subframe sets C _{CSI, 0} , C _{CSI, 1} through a higher layer, the operation of the measurement reset method proposed in the first embodiment of the present disclosure Let's explain.

Unlike the embodiments 1-4, 1-5, and 1-6 of the present disclosure, the first through seventh embodiments of the present disclosure measure a window for a case where a new TM for operating an FD-MIMO system is defined. It is about an operation method.

The size of the measurement window may be set to higher layer signaling or may be fixedly defined assuming that the FD-MIMO system always operates with beamformed CSI-RS without setting higher layer signaling. That is, when the base station is configured with a new TM can be operated by using a fixed size of the measurement window.

In the first to seventh embodiments of the present disclosure, unlike the first to fourth, first and fifth embodiments of the present disclosure, higher layer signaling may not be additionally set. For example, when the base station is configured with a new TM, the measurement window configuration may be set to 0 in Table 6, and the channel estimation value for the CSI-RS may be initialized for every CSI-RS reception.

In the first to eighth embodiments of the present disclosure, when the UE is set to CSI subframe sets C _{CSI, 0} and C _{CSI, 1} through a higher layer, the measurement reset trigger or measurement window proposed in the first embodiment of the present disclosure is performed. It is about how to operate using.

First, when using the measurement reset trigger, the UE may be configured to perform the measurement reset only for the CSI subframe set to which the measurement reset trigger is transmitted. Next, in the case of using the measurement window, the terminal may be set to define the measurement window as the number of transmitted CSI-RS and to perform measurement reset only for the CSI subframe set having the measurement window.

Embodiments 1-9 of the present disclosure relate to a method for a UE to perform CSI reporting when a measurement restriction is applied through a measurement reset trigger or a measurement window proposed in the first embodiment of the present disclosure. The CSI reporting may be performed by being divided into Aperiodic CSI reporting or Periodic CSI reporting.

First, in consideration of the case of operating with Aperiodic CSI reporting, when measurement restriction is performed through a measurement reset trigger, as described with reference to FIG. 9 of the first-first embodiment of the present disclosure, the BS performs a measurement reset trigger and an Aperiodic CSI request. The transmission at the time when the CSI-RS is transmitted is effective in performing measurement restriction and performing Aperiodic CSI reporting. In this case, the UE may perform measurement by using the CSI-RS at the time n when the measurement reset trigger and the Aperiodic CSI request are transmitted and perform Aperiodic CSI reporting at the time n + k. If the measurement restriction is made through the measurement window, if n is the time when the Aperiodic CSI request is transmitted in the measurement window, the UE performs the measurement using the previous CSI-RS and performs Aperiodic CSI reporting at the time n + k. can do.

Next, consider the case of working with Periodic CSI reporting. In the case of Periodic CSI reporting, the feedback timing is determined by the four feedback modes of Table 7. 2. 2-1 of 3GPP TS 36. 213 and parameters transmitted through higher layer signals. Details thereof will be described with reference to FIGS. 4 to 7. In the case of periodic CSI reporting, it is necessary to specify RI / PMI / CQI feedback that reflects the measurement restriction from the time when measurement restriction is applied through a measurement reset trigger or a measurement window. For example, since feedback is performed in order of RI, PMI, and CQI, and CQI is calculated based on previously fed RI and PMI, CQI reflects the result of measurement restriction if the measurement restriction occurs after the PMI feedback. Can not. Therefore, if measurement restriction is made through measurement reset trigger or measurement window, the reflection of this should be updated based on RI. For example, referring to FIG. 6, when measurement restriction is performed at n = 5 in FIG. 6, RI / PMI / CQI reflecting a measurement reset from n = 16 may be reported. In this case, PMI / CQI information transmitted between n = 5 to 15 cannot be used. If measurement restriction is performed through the measurement window, the measurement window may be set in consideration of the period in which the RI is reported as described above. As such, when the measurement window is set to feedback timing considering the period in which the RI is reported, the PMI / CQI information is discarded after the measurement restriction is made as described above.

In the first to tenth embodiments of the present disclosure, as described in the measurement window, M NZP CSIs are used for channel measurement based on the definition of measurement restriction in a method different from a method of informing a measurement window period in which a measuremet reset is performed at a predetermined period. A method of configuring an RS subframe or configuring N CSI-IM subframes for interference measurement will be described. As described in the measurement window, M or N values may be configured using higher layer signaling. More specifically, it may be operated through Table 11 below. In addition, the method of setting this to higher layer signaling adds the following fields to the CSI-RS configuration, the CSI process, or the CSI report configuration as in the embodiments 1-4, 1-5, and 1-6 of the present disclosure. It is possible by doing.

-CSI-RS-MeasurementRestrictionConfig INTEGER (0. .X) or INTEGER (A, X)

-CSI-IM-MeasurementRestrictionConfig INTEGER (0 .. X) or INTEGER (A, X)

In this case, the integer X may be interpreted as not performing a measurement reset. In addition, note that the INTEGER (A.X) is indicated when one measurement restriction is fixed as INTEGER (0. .X) for the case of operation with various measurement restriction configurations. Specifically, when A is set to 1, M = 1 or N = 1 is set to measure a channel through one NZP CSI-RS subframe or measure interference through one CSI-IM subframe.

TABLE 11

In the first to eleventh embodiments of the present disclosure, as described in the embodiments 1-4, 1-5, and 1-6 of the present disclosure, the CSI− subframe configuration of the measurement window is described in the method of operating the measurement window. The present invention relates to a method of configuring a subframe configuration of a measurement window for a case in which additional configuration through RS signaling, CSI process, and CSI report configuration cannot be additionally set through signaling. In the first to eleventh embodiments of the present disclosure, it is possible to consider the following two methods.

The subframe configuration (measuring window period and subframe offset) of the measurement window may be used in the same meaning as a beam indicator (BI) (and the BI is a CSI-RS resource indicator (CRI)). It is determined by the period and subframe offset. Here, CRI represents an index of CSI-RS resources for K CSI-RS resources.

The subframe configuration (measurement window period and subframe offset) of the measurement window is determined by the period and subframe offset of the RI.

For example, when the subframe configuration of the measurement window is determined by the CRI, it means that the period and subframe offset of the measurement window are determined by the period and offset of the CRI defined by higher layer signaling. If the period of the CRI is A ms and the offset is the B subframe, the period and the subframe offset of the measurement window may be determined as the A ms and (Y-x) subframes, respectively. Where x can be set to any integer.

Embodiments 1-12 of the present disclosure relate to a method for setting measurement restriction of a base station and a terminal according to Periodic CSI reporting or Aperiodic CSI reporting. In the first to twelve embodiments of the present disclosure, a method of applying a measurement restriction scheme may vary according to periodic CSI reporting or Aperiodic CSI reporting as shown in FIG. 13.

13 and 14 illustrate a method of setting a measurement limiting technique according to embodiments 1-12 of the present disclosure.

Referring to FIG. 13, as the CSI reporting method is set to Periodic CSI reporting or Aperiodic CSI reporting, a measurement restriction technique applied may vary. That is, the base station and the terminal set Periodic CSI reporting or Aperiodic CSI reporting as the CSI reporting method (1301). The CSI reporting method set by the base station and the UE is determined (1303), and the measurement limiting technique A is applied in the case of the Periodic CSI reporting method (1305), and the measurement limiting technique B is applied in the case of the Aperiodic CSI reporting method (1307).

The measurement limiting technique applied here is a first method for the measurement reset trigger proposed in the first embodiment of the present disclosure (Examples 1-1, 1-2, and 1-3), and a second method for the measurement window. Method (Examples 1-4, 1-5, 1-6, and 1-11) and the case where the number M / N of the subframes to which the measurement restriction is applied is set to one or more fixed numbers. It includes all third methods (Examples 1-10).

For example, when the CSI reporting method is set to Aperiodic CSI reporting, the third method may be applied. When the CSI reporting method is set to Periodic CSI reporting, the second method may be applied.

Next, referring to FIG. 14, as the CSI reporting method is set to Periodic CSI reporting or Aperiodic CSI reporting, application of ON / OFF to measurement restriction may be different.

That is, the base station and the terminal set Periodic CSI reporting or Aperiodic CSI reporting as the CSI reporting method (1401). When the CSI reporting method set by the base station and the UE is determined (1403), the measurement restriction is applied when the Aperiodic CSI reporting is set (1407), and the measurement restriction is not applied when the periodic CSI reporting is set. In other words, measurement restriction applies only to Aperiodic CSI reporting. Therefore, as described in embodiments 1-9 of the present disclosure, it is possible to prevent a problem that may occur when the measurement restriction is applied to Periodic CSI reporting.

Embodiment 11-13 of the present disclosure relates to a method for setting measurement restriction of a base station and a terminal with respect to a channel or interference. In the 3GPP RAN1 # 82b meeting, it was decided to support only measurement restriction on interference using CSI-IM for Class A, and to use CSI-IM for channel B using measurement restriction and CSI-IM for channels. It was decided to support all measurement restrictions on interference. Based on this decision, we propose a method of applying measurement constraints to channels or interference.

As in the first to twelve embodiments of the present disclosure, the measurement restriction method proposed in the first to third embodiments of the present disclosure may include a first method for a measurement reset trigger, a second method for a measurement window, and a measurement restriction. The second method includes the case where the number M / N of subframes to be set is one or more than one fixed number.

15 illustrates a method of setting a measurement limiting technique according to embodiment 1-13 of the present disclosure.

Referring to FIG. 15, the base station and the terminal check the class for the CRS-RS (1501). The base station and the terminal determine whether the identified Class is Class A (1503), and in the case of Class A, the base station and the terminal determine whether the measurement restriction is to be applied to the channel or interference (1505). As described above, since the base station and the terminal may apply a measurement restriction on interference for Class A, the base station and the terminal apply the measurement restriction in one subframe to interference (1507). This focuses on the fact that measurement restriction can be changed every subframe in case of interference. The first method, the second method, and the third method for the measurement restriction may all be configured to operate as the measurement restriction in one subframe. On the other hand, the base station and the terminal does not apply the measurement restriction for the channel in case of Class A (1509).

On the other hand, when the base station and the terminal determines that the identified class is not Class A (that is, Class B), it determines whether to apply the measurement restriction to the channel or interference (1509). As described above, the base station and the terminal may apply a measurement restriction on the channel and interference for Class B. Therefore, in case of Class B, the base station and the terminal apply measurement restriction in one subframe to interference (1507), and apply channel restriction technique X for the channel (1513). Here, the channel limiting technique X means using one of the first method, the second method and the third method. For example, when the third method is applied, reference numerals 1507 and 1511 may be set to N = 1, and reference numeral 1513 may be set to M = 1 or M> 1.

Hereinafter, operations of a base station and a terminal performing the first embodiment of the present disclosure will be described. 16 illustrates a method of measuring a channel in a base station according to the first embodiment of the present disclosure. FIG. 16 illustrates the operation of a base station when operating based on a beamformed CSI-RS in an FD-MIMO system. Meanwhile, the method for measuring a channel according to the first embodiment of the present disclosure may be applied to a CSI-IM as well as a beamformed CSI-RS.

Referring to FIG. 16, the base station sets information for channel measurement (1601). In this case, setting information for channel measurement may be performed through the methods proposed in the first embodiment of the present disclosure. Thereafter, the base station transmits configuration information configured for channel measurement to the terminal (1603). If the base station is set to the information for the channel measurement based on the measurement reset trigger, the information is basically transmitted through the L1 signaling, additional information that needs to be set may be transmitted through the higher layer signaling. Here, since the detailed operation thereof has been described in detail in the embodiments 1-1 to 1-3 of the present disclosure, it will be omitted. If information for channel measurement is set based on a measurement window, the information may be transmitted through higher layer signaling. Here, since the detailed operation thereof has been described in detail in the embodiments 1-4, 1-5, 1-6, and 1-11 of the present disclosure, it will be omitted. In addition, if the UE is configured with CSI subframe sets during CSI operation, the related operation will be described with reference to Embodiments 1-8 of the present disclosure.

17 illustrates a method of measuring a channel in a terminal according to the first embodiment of the present disclosure. FIG. 17 illustrates an operation of a terminal when operating based on a beamformed CSI-RS in an FD-MIMO system. Meanwhile, the method for measuring a channel according to the first embodiment of the present disclosure may be applied to a CSI-IM as well as a beamformed CSI-RS.

Referring to FIG. 17, a terminal receives configuration information for channel measurement from a base station (1701). The terminal checks the received channel measurement information to determine whether the channel measurement information is initialized and set (1703). If the channel measurement information is initialized, the terminal performs channel measurement (1705). The terminal generates CSI information (1707) and transmits CSI information to the base station at a predetermined timing (1709). The operation of the terminal related to this will be described with reference to the embodiment 1-9.

In the above, a method of measuring channels of a base station and a terminal according to the first embodiment of the present disclosure has been described. Hereinafter, an operation of measuring a channel according to the first embodiment of the present disclosure will be described based on FIGS. 18 and 19. An internal configuration of the base station and the terminal to be performed will be described.

FIG. 18 schematically illustrates an internal configuration of a base station for measuring a channel in an FD-MIMO system according to a first embodiment of the present disclosure.

Referring to FIG. 18, the base station 1800 includes a controller 1801, a transmitter 1803, a receiver 1805, and a storage 1807.

The controller 1801 controls the overall operation of the base station 1800, and in particular, controls the operation related to the operation of measuring the channel according to the first embodiment of the present disclosure. Operations related to measuring channels according to the first embodiment of the present disclosure are the same as those described with reference to FIGS. 8 to 16, and thus, detailed description thereof will be omitted.

The transmitter 1803 receives various signals and various messages from other entities included in the communication system under the control of the controller 1801. Here, since various signals and various messages received by the transmitter 1803 are the same as those described with reference to FIGS. 8 to 16, detailed descriptions thereof will be omitted.

In addition, the receiver 1805 receives various signals and various messages from other entities included in the communication system under the control of the controller 1801. Here, various signals and various messages received by the receiver 1805 are the same as those described with reference to FIGS. 8 to 16, and thus, detailed description thereof will be omitted.

The storage unit 1807 stores a program and various data related to an operation of measuring a channel according to the first embodiment of the present disclosure performed by the base station 1800 under the control of the controller 1801. In addition, the storage unit 1807 stores various signals and various messages received by the receiving unit 1805 from the other entities.

Meanwhile, FIG. 18 illustrates a case in which the base station 1800 is implemented as separate units such as the controller 1801, the transmitter 1803, the receiver 1805, and the storage 1807. 1800 may be implemented in an integrated form of at least two of the controller 1801, the transmitter 1803, the receiver 1805, and the storage 1807. In addition, of course, the base station 1800 may be implemented by one processor.

19 is a diagram briefly illustrating an internal configuration of a terminal for measuring a channel in an FD-MIMO system according to a first embodiment of the present disclosure.

Referring to FIG. 19, the terminal 1900 includes a controller 1901, a transmitter 1901, a receiver 1905, and a storage 1907.

The controller 1901 controls the overall operation of the terminal 1900, and in particular, controls an operation related to an operation of measuring a channel according to the first embodiment of the present disclosure. Since the operation related to the operation of measuring the channel according to the first embodiment of the present disclosure is the same as described with reference to FIGS. 8 to 17, a detailed description thereof will be omitted.

The transmitter 1903 receives various signals and various messages from other entities included in the communication system under the control of the controller 1901. Here, various signals and various messages received by the transmitter 1901 are the same as those described with reference to FIGS. 8 to 17, and thus, detailed description thereof will be omitted.

In addition, the receiver 1905 receives various signals and various messages from other entities included in the communication system under the control of the controller 1901. Here, the various signals and the various messages received by the receiver 1905 are the same as those described with reference to FIGS. 8 to 17, and thus detailed description thereof will be omitted.

The storage unit 1907 stores a program and various data related to an operation of measuring a channel according to the first embodiment of the present disclosure performed by the terminal 1900 under the control of the controller 1901. In addition, the storage unit 1907 stores various signals and various messages received by the receiving unit 1905 from the other entities.

19 illustrates a case in which the terminal 1900 is implemented as separate units such as the controller 1901, the transmitter 1901, the receiver 1905, and the storage unit 1907, the terminal ( 1900 may be implemented in an integrated form of at least two of the controller 1901, the transmitter 1901, the receiver 1905, and the storage 1907. In addition, the terminal 1900 may be implemented by one processor.

A second embodiment of the present disclosure relates to a method and apparatus for measuring interference in order for a terminal to generate channel state information in a mobile communication system performing MIMO transmission using a plurality of transmit antennas at an eNB.

20 is a diagram illustrating a communication system to which an embodiment of the present disclosure is applied.

Referring to FIG. 20, a base station transmits a radio signal using dozens or more transmission antennas. The plurality of transmit antennas are arranged to maintain a certain distance as shown in FIG. The predetermined distance may correspond to, for example, a multiple of half the wavelength of the transmitted radio signal. In general, when the distance that is half of the wavelength of the radio signal is maintained between the transmitting antennas, the signals transmitted from each transmitting antenna are affected by the radio channel having low correlation with each other. The farther the transmission antenna is, the smaller the correlation between the signals.

A base station having a large antenna may arrange the antennas in two dimensions as shown in FIG. 20 to prevent the size of the transmission apparatus included in the base station from becoming very large. In FIG. 20, a base station transmits a signal using N _H antennas arranged on a horizontal axis and N _V antennas arranged on a vertical axis, and a terminal needs to measure a channel for the corresponding antenna.

In FIG. 20, dozens or more transmit antennas disposed in a base station are used to transmit signals to one or more terminals. Appropriate precoding is applied to the plurality of transmit antennas so that signals are simultaneously transmitted to the plurality of terminals. In this case, one terminal may receive one or more information streams. In general, the number of information streams that a single terminal can receive is determined according to the number of reception antennas and the channel conditions of the terminal.

In order to effectively implement the MIMO system, as described above, the terminal accurately measures the channel condition and the magnitude of interference, and transmits the effective channel state information to the base station using the same. Upon receiving the channel state information, the base station uses the same to determine which terminals to transmit, at what data rate, and to which precoding to apply to downlink transmission. In the case of the FD-MIMO system, since the number of transmitting antennas is large, an uplink overhead problem in which a large amount of control information needs to be transmitted in uplink occurs when the conventional channel state transmission / reception method of the LTE / LTE-A system is applied.

Time, frequency and power resources are limited in mobile communication systems. Therefore, allocating more resources to the reference signal reduces the resources that can be allocated for data traffic channel transmission, thereby reducing the absolute amount of data transmitted. In this case, the performance of channel measurement and estimation will be improved, but the overall system capacity performance may be lowered because the absolute amount of data transmitted is reduced.

Therefore, an appropriate allocation is needed between the resources for the reference signal and the resources for the traffic channel transmission in order to obtain optimal performance in terms of overall system capacity.

In the case of a base station having a large antenna, as shown in FIG. 20, resources for measuring channels of 8 or more antennas should be configured and transmitted to a terminal. For example, a maximum of 40 REs can be used as an available resource. Only two, four or eight can be used. Therefore, in order to support channel measurement for the large-scale antennas required by the FD-MIMO system, CSI-RS patterns for 16 and 32 which are not supported by the current system are required, and these CSI-RS patterns are accurate and efficient. For CSI generation, it should be designed considering various aspects such as power boosting and wireless channel estimator implementation.

In addition, in a base station that used four horizontal dimension antennas in a conventional base station, when the vertical dimension antenna is used to improve performance, the applicable size of the antenna may not necessarily be four or eight. Therefore, a new design is also required for the CSI-RS pattern for supporting 12 antennas used as three vertical antennas to support this and various other antenna numbers.

Therefore, the FD-MIMO system should consider a larger number of antennas to generate channel state information reported to the base station compared to the conventional LTE system, and for this purpose, a larger number of reference signals should be transmitted and received. . Accordingly, a second embodiment of the present disclosure is to provide a method and apparatus for reflecting a reference signal transmitted and received in a channel state information by a terminal transmitting and receiving a greater number of reference signals in an FD-MIMO system.

Embodiment 2-1 of the present disclosure is a method for supporting twelve CSI-RS ports.

FIG. 21 shows that twelve CSI-RS ports are supported using existing CSI-RS REs in a mobile communication system according to embodiment 2-1 of the present disclosure.

As described above, a total of 40 CSI-RS REs of one PRB are included. Here, the second embodiment of the present disclosure defines a CSI-RS port except for four existing CSI-RS REs in order to support 12 CSI-RS ports in a current 40 CSI-RS RE. . When using the CSI-RS port by adding new REs instead of using the currently defined CSI-RS REs, the corresponding REs should not be used as PDSCH for existing UEs that do not currently use the corresponding REs as CSI-RS REs. Therefore, the data cannot be transmitted to the corresponding RE. That is, data puncturing occurs when adding new REs and using them as CSI-RS ports instead of using currently defined CSI-RS REs. In addition, existing terminals decode the PDCSH by considering the CSI-RS as a data signal because there is no means for receiving the information on the data puncturing, and thus, the CSI-RS of the corresponding RE interferes with the existing terminals. Will act as. In order to prevent such data puncturing and interference, the CSI-RS port should be configured using only existing CSI-RS REs. However, in this case, since there are 40 CSI-RS REs previously defined, four REs should not be used, and the number of configurable settings is limited to three in one RB. As such, the small number of configurable settings means that the number of cases where neighboring cells and terminals can multiplex in a time and frequency dimension avoiding each other's CSI-RS location is reduced.

In the case of the existing 4 and 8 port CSI-RS, the CSI-RS ports under the same configuration are transmitted using the same time resources in order to maximize the performance of the wireless channel estimation through the reference signal. Accordingly, a 3dB power gain can be achieved in the case of 4 port CSI-RS and a 6dB power boosting effect can be achieved in the case of 8 port CSI-RS. However, in the case of the CSI-RS pattern of FIG. 21, in the case of the configuration (config) B and the C, all the reference signals can obtain a power boosting effect of about 7.8 dB (6 times) using the same time resource. In this case, only 4.8 dB (3 times) of power boosting is possible, and although the number of antennas is larger than the existing 8 port CSI-RS, the power boosting effect cannot be sufficiently obtained. In addition, when the measured OFDM symbol is different, a phase shift may occur due to a time difference between the two symbols and a residual frequency offset, which may affect the PMI estimation performance.

Similarly, in order to minimize the hardware complexity of the conventional CSI-RS, only the RE starting point is different according to all CSI-RS configurations and has the same RS structure. However, in the embodiment 2-1 of the present disclosure, in the case of a pattern according to CDM 2 having two sizes, such a consideration cannot be taken to support 12 CSI-RS ports in an existing CSI-RS location. have. In embodiment 2-1 of the present disclosure, a resource configuration for 12 port CSI-RS considering a pattern according to CDM 2 may be configured as shown in Table 12 below. To this end, the base station sets the CSI-RS configuration (CSI reference signal configuration) to the terminal dynamic (dynamic) or semi-static (semi-static), and to share the CSI-RS configuration with the terminal as shown in Table 12 In the embodiment 2-1 of the present disclosure, CSI-RS resource configuration method (normal CP) according to CDM 2 may be previously defined in a standard.

TABLE 12

Here, p is a port index of the port, and the port of the 0 th antenna is represented by 15. When the antenna index increases, the port index also increases. At this time, for example, the symbol a of the 12 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 2 below.

here,

Same as

By using Equation 2, the terminal sets k ', l',

,

, Cp type (normal cyclic prefix or the extended cyclic prefix) and W _l _", through n _s l '', m 'can be derived the parameters, such as are received in the CSI-RS necessary for the CSI-RS received, it is based on The symbol a of the 12 port CSI-RS transmitted in the position k th frequency RE and the l th time symbol can be derived.

Is the largest downlink bandwidth setting that can be set,

Is the actual downlink bandwidth setting configured in the terminal and n _s is the slot number in the radio frame.

In addition, in Example 2-1 of the present disclosure, it is assumed that the CDM has a size of CDM 2. However, if the power boosting of the CSI-RS port is difficult due to hardware limitations and inter-modulation, etc., it is difficult to apply CDM 4 with 4 sizes. have. When using two sizes of CDM 2, {0,1}, {2,3}, {4,5}, {6,7},. . . , {30,31} in order, and are sent from the same two REs. When using CDM 4 with four sizes, {0,1,2,3}, {4,5,6,7} , {8,9,10,11},. . . 4 ports are transmitted in 4 identical REs in the order of {28,29,30,31}. In addition, the port combinations for various CDMs, such as {0,1,6,7}, {2,3,8,9}, {4,5,10,11}, in consideration of RE position and port order are also possible. You must keep in mind. Equation 3 below is an example of a CDM scheme having two sizes and four sizes when having 12 CSI-RS ports.

In the embodiment 2-1 of the present disclosure and the resource configuration for the 12 port CSI-RS in consideration of the pattern according to the CDM 4 may be configured as shown in Table 13 below. Table 13 below shows a CSI-RS resource configuration method (normal CP) according to CDM 4 in embodiment 2-1 of the present disclosure.

TABLE 13

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. In this case, for example, the symbol a of the 12 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 3 below.

here,

Same as

As defined above, the CDM 4 is assigned to four codes (1,1,1,1), (1, -1,1, -1), (1,1, -1, -1), and (-1, -1,1,1), and not only the second embodiment of the present disclosure but also other embodiments described below also use CDM 2 It should be borne in mind that the above expression is possible using 4.

FIG. 22 illustrates CSI-RS patterns for 12 port configured based on embodiment 2-1 of the present disclosure. Resource configuration and 12 port CSI-RS symbol illustrated in embodiment 2-1 of the present disclosure. A similar definition can be used. The current Rel-10 8Tx codebook and Rel-12 4Tx codebook of LTE assume that the first four or two antennas are polarized at +45 degrees and the next four or two antennas are polarized at -45 degrees. Was designed. If the codebook for supporting 12 CSI-RS ports is designed under the same principle, beam selection is the same phase by time difference when 0-5 and 6-11 ports are transmitted through the same OFDM symbol. Relatively little errors can be selected by experiencing the transition and reflecting only the phase shift difference due to the frequency difference. On the other hand, phase shift due to time difference is concentrated in co-phasing between antennas having different polarizations, and thus an error may increase in a corresponding portion. In contrast, when transmitted through OFDM symbols at different times, a phase shift may occur only in OFDM symbols of some ports among antennas having the same polarization, which may cause the same level of error in beam selection and co-phasing determined by the UE. . However, this pattern has the advantage of being able to reflect the error over time in beam selection and co-phasing within a single RB.

<2-2 Example>

Embodiment 2-2 of the present disclosure is a method for supporting 16 CSI-RS ports.

FIG. 23 shows that 16 CSI-RS ports are supported using existing CSI-RS REs in a mobile communication system according to embodiment 2-2 of the present disclosure.

As described above, a total of 40 CSI-RS REs of one PRB are included. Here, in the second embodiment of the present disclosure, in order to support 16 CSI-RS ports in 40 CSI-RS REs, only 32 REs are excluded except for 8 existing CSI-RS REs. to define the port. As mentioned above, when using the CSI-RS port by adding new REs instead of using the currently defined CSI-RS REs, the corresponding REs are currently used for existing UEs that do not use the corresponding REs as CSI-RS REs. Should not be used as a PDSCH, thus preventing data transmission to the corresponding RE. That is, data puncturing occurs when adding new REs and using them as CSI-RS ports instead of using currently defined CSI-RS REs. In addition, existing terminals decode the PDCSH by considering the CSI-RS as a data signal because there is no means for receiving the information on the data puncturing, and thus, the CSI-RS of the corresponding RE interferes with the existing terminals. Will act as. As such, to prevent data puncturing and interference, the CSI-RS port should be configured using only existing CSI-RS REs. However, in this case, since there are 40 CSI-RS REs defined previously, 8 REs should not be used, and the number of configurable settings is limited to 1 for one RB. The small number of such configurable settings means that the number of cases in which multiple cells and terminals in the vicinity can multiplex in a time and frequency dimension avoiding each other's CSI-RS location is reduced.

In the case of the existing 4 and 8 port CSI-RS, the CSI-RS ports under the same configuration are transmitted using the same time resources in order to maximize the performance of estimating the radio channel through the reference signal. Accordingly, a 3dB power gain can be achieved in the case of 4 port CSI-RS and a 6dB power boosting effect can be achieved in the case of 8 port CSI-RS. However, in the case of the CSI-RS pattern of FIG. 23, reference signals of 4-15 ports can obtain a power boosting effect of 6 dB using the same time resource, but in the case of 0-3 ports, only 3 dB power boosting is achieved. As a result, despite the fact that the number of antennas is larger than that of the existing 8 port CSI-RS, the power boosting effect may not be sufficiently obtained, and the maximum power boosting value that can be considered in the configuration for one CSI-RS 16 port may be considered. shall.

In the case of the pattern according to the embodiment 2-2 of the present disclosure, in order to minimize the hardware complexity of the terminal as in the conventional CSI-RS, only the RE starting point is different according to all CSI-RS configurations and has the same RS structure. However, in consideration of the same power boosting or the existing ZP-CSI-RS structure, the RS structure may be designed differently according to each setting, which is described with reference to FIGS. 24A and 24B. 24A and 24B illustrate CSI-RS patterns for 16 ports based on embodiment 2-2 of the present disclosure. Resource configuration and 16 port CSI- illustrated in embodiment 2-2 of the present disclosure. It can be used using a definition similar to an RS symbol.

Resource configuration for the 16 port CSI-RS considering the pattern according to the embodiment 2-2 of the present disclosure may be configured as shown in Table 14 below. Table 14 below shows a CSI-RS resource configuration method (normal CP) according to embodiment 2-2 of the present disclosure.

TABLE 14

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. At this time, for example, the symbol a of the 16 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 4 below.

here,

Same as

Embodiment 2-3 of the present disclosure is a method for supporting 32 CSI-RS ports.

FIG. 25 illustrates that 32 CSI-RS ports are supported by using existing CSI-RS REs in a mobile communication system according to embodiment 2-3 of the present disclosure.

As described above, a total of 40 CSI-RS REs of one PRB are included. Here, in the second embodiment of the present disclosure, in order to support 32 CSI-RS ports in 40 CSI-RS REs, only one RE is configured with only 32 REs except 8 existing CSI-RS REs. RS 32 port is defined in PRB. As mentioned above, when using the CSI-RS port by adding new REs instead of using the currently defined CSI-RS REs, the corresponding REs are currently used for existing UEs that do not use the corresponding REs as CSI-RS REs. Should not be used as a PDSCH, thus preventing data transmission to the corresponding RE. That is, data puncturing occurs when adding new REs and using them as CSI-RS ports instead of using currently defined CSI-RS REs. In addition, existing terminals decode the PDCSH by considering the CSI-RS as a data signal because there is no means for receiving the information on the data puncturing, and thus, the CSI-RS of the corresponding RE interferes with the existing terminals. Will act as. As such, in order to prevent data puncturing and interference, the CSI-RS port should be configured using only existing CSI-RS REs. However, in this case, since there are 40 CSI-RS REs defined previously, 8 REs should not be used, and the number of configurable settings is limited to 1 for one RB. The small number of such configurable settings means that the number of cases in which multiple cells and terminals in the vicinity can multiplex in a time and frequency dimension avoiding each other's CSI-RS location is reduced.

In the case of the existing 4 and 8 port CSI-RS, the CSI-RS ports under the same configuration are transmitted using the same time resources in order to maximize the performance of estimating the radio channel through the reference signal. Accordingly, a 3dB power gain can be achieved in the case of 4 port CSI-RS and a 6dB power boosting effect can be achieved in the case of 8 port CSI-RS. When all 32 CSI-RS ports are arranged in the same time resource, a maximum power boosting effect of 12 dB can be obtained. However, the current RB structure of LTE is impossible because only 12 REs are arranged in frequency resources. In the CSI-RS pattern according to the embodiment 2-3 of the present disclosure as shown in FIG. 25, reference signals of 0-7 ports are the same as 8 ports, and a power boosting effect of 6 dB can be obtained. For the port, 10.8dB power boosting is possible. If the power amplifier of the base station supports 10.8 dB power boosting, and only a part of the ports in the entire CSI-RS port determines that higher accuracy is advantageous through higher power boosting, as shown in FIG. By arranging a large number of CSI-RS ports, you can design a CSI-RS pattern to use the maximum power of some of the ports. As such, the resource configuration for the 32 port CSI-RS considering the pattern according to the embodiment 2-3 of the present disclosure may be configured as shown in Table 15 below. Table 15 below shows a CSI-RS resource configuration method (normal CP) according to embodiment 2-3 of the present disclosure.

TABLE 15

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. At this time, for example, the symbol a of the 32 port CSI-RS transmitted on the k th frequency RE and the l th time symbol may be defined as in Equation 5 below.

here,

Same as

FIG. 26 illustrates CSI-RS patterns for 32 port configured based on Embodiment 2-3 of the present disclosure. Resource configuration and 32 port CSI-RS symbol illustrated in Embodiment 2-3 of the present disclosure. A similar definition can be used.

Embodiment 2-4 is a method for supporting twelve CSI-RS ports.

FIG. 27 illustrates that twelve CSI-RS ports are supported by additionally using REs used as PDSCHs as well as existing CSI-RS REs in a mobile communication system according to embodiments 2-4 of the present disclosure.

As described above, a total of 40 CSI-RS REs of one PRB are included. Therefore, when 8 PDSCH REs are additionally used to make the total number of CSI-RS REs in multiples of 12, the total number of CSI-RS REs is 48 so that four 12 port CSI-RSs can be used in one RB. . In the second embodiment of the present disclosure, as shown by reference numeral 2710 of FIG. 27, four 12 ports are additionally used by additionally using 8 PDSCH REs of

OFDM symbols #

5 and 6 and

OFDM symbols #

12 and 13 of the entire RB. To create a CSI-RS. In case of additionally using the PDSCH RE in place in contrast to using the PDSCH RE elsewhere in the embodiment 2-4 of the present disclosure, the reference signal structures of all CSI-RS configurations are not exactly the same, but will have a similar structure. Can be. In the second embodiment of the present disclosure, all 12 CSI-RS ports exist in the same time resource, enabling power boosting of up to 7.8 dB (6 times), thereby improving channel estimation performance through a reference signal. You can. In addition, in the second to fourth embodiments of the present disclosure, since the number of configurations that can be configured in a maximum of one PRB is 4, several cells and terminals avoid the CSI-RS location of each other than when using conventional CSI-RS REs. In the frequency dimension, more multiplexing can be avoided by mutual interference. However, when using this method, as described above, existing UEs must puncturing PDSCHs of corresponding REs. In addition, the existing UEs are decoded by considering the CSI-RS as a PDSCH because there is no means for receiving information on puncturing, and thus the CSI-RS of the corresponding RE acts as an interference to the existing UEs. Resource configuration for the 12 port CSI-RS considering the pattern according to the embodiment 2-4 of the present disclosure may be configured as shown in Table 16. Table 16 below shows a CSI-RS resource configuration method (normal CP) according to embodiments 2-4 of the present disclosure.

TABLE 16

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. In this case, for example, the symbol a of the 12 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 6 below.

here,

Same as

FIG. 28 illustrates CSI-RS patterns for 12 port configured based on embodiment 2-4 of the present disclosure. Resource configuration and 12 port CSI-RS symbol illustrated in embodiment 2-4 of the present disclosure. A similar definition can be used.

The embodiments shown in FIG. 28 differ in that the CSI-RS pattern of FIG. 27 is transmitted in another OFDM symbol while each setting is transmitted in the same OFDM symbol. In this case, the CSI of FIG. Channel estimation performance may be lower than that of the -RS pattern. In addition, when the measured OFDM symbol is different, a phase shift may occur due to a time difference between the two symbols and a residual frequency offset, which may affect the PMI estimation performance.

Embodiment 2-5 is a method for supporting twelve CSI-RS ports.

FIG. 29 illustrates an additional 12 CSI using additional REs used as PDSCHs as well as existing CSI-RS REs to support 12 CSI-RS ports in a mobile communication system according to embodiments 2-5 of the present disclosure. -RS port is shown to be supported.

As described above, a total of 40 CSI-RS REs of one PRB are included. Therefore, when 48 REs are used as CSI-RS REs to make the total number of CSI-RS REs in multiples of 12, four 12 port CSI-RSs may be used in one RB. Embodiment 2-5 of the present disclosure additionally uses 24 PDSCH REs of

OFDM symbols

2 and 3 of all RBs as shown by reference numeral 2910 of FIG. 29, and uses

OFDM symbols

5 and 6 as shown by reference numeral 2920. 4 12 port CSI-RSs are generated except 16 REs used in OFDM symbols # 12 and # 13. In case of using the embodiment 2-5 of the present disclosure, all CSI-RS configuration reference signals may use the same structure, and all 12 CSI-RS ports exist in the same time resource, so that a maximum of 7.8 dB ( 6x) power boosting can improve the channel estimation performance through the reference signal. In addition, when using the embodiment 2-5 of the present disclosure, since the number of configurations that can be configured in a maximum of one PRB is 4, several cells and terminals are located at each other's CSI-RS location more than the existing CSI-RS REs. Multiplexing can be avoided by avoiding mutual interference in terms of damage time and frequency. However, as described above, existing UEs must puncturing PDSCHs of corresponding REs. In addition, the existing UEs are decoded by considering the CSI-RS as a PDSCH because there is no means for receiving information on puncturing, and thus the CSI-RS of the corresponding RE acts as an interference to the existing UEs.

Unlike the second to fourth embodiments of the present disclosure, in the case of the CSI-RS pattern of the second to fifth embodiments of the present disclosure, an OFDM symbol # 2 usable as a PDCCH symbol is used. The PDCCH contains control-related information that is very important to the UE and cannot be solved by simply puncturing the information. Therefore, in this case, the total number of PDCCH symbols should be limited to two existing terminals and new terminals, and it should be informed that two PDCCH symbols are provided through the PCFICH. However, even though the number of PCFICH symbols is three, if the CSI-RS is configured in the corresponding subframe can be solved through the following methods.

Method 1: Ignore the CSI-RS setting and follow PCFICH.

Second method: determine that the PCFICH is set incorrectly and measure the channel through CSI-RS.

In the first method, when the number of PDCCH OFDM symbols indicated by the PCFICH is 3, all of the CSI-RSs set in the corresponding subframe are ignored. In this case, when the CSI-RS pattern of FIG. 29 is used, a portion overlapping the PDCCH symbol appears in all the CSI-RS configurations, resulting in the use of 12 port CSI-RS in the corresponding subframe. Therefore, in the embodiments 2-5 of the present disclosure, in order to consider the CSI-RS pattern based on the first method, the pattern shown in FIG. 30 may be used.

FIG. 30 illustrates a CSI-RS pattern designed based on the first method in embodiments 2-5 of the present disclosure.

In the case of the pattern shown in FIG. 30, there are two settings located in symbol 2 that can be used as the PDCCH, and the remaining settings can be used as CSI-RS. In addition, in the case of the pattern shown in FIG. 30, since all CSI-RS ports are transmitted in the same OFDM symbol, a power boosting value of up to 7.8 dB (6 times) is available, and thus compared with the pattern shown in FIG. 29. The advantage is that more power boosting is available if the hardware can support it.

In the second method, when the 12-port CSI-RS configured in the corresponding subframe exists in the PDCCH OFDM symbol region, it is determined that the PCFICH is transmitted incorrectly, and the PCFICH is assumed to be 2 and used. In the case of the second method, the channel is not measured in the configured CSI-RS port. However, when the actual PDCCH uses three OFDM symbols and the CSI-RS port is not transmitted, the operation may not be performed properly.

In an embodiment 2-5 of the present disclosure, a resource configuration for 12 port CSI-RS considering the pattern illustrated in FIG. 29 may be configured as shown in Table 17 below. Table 17 below shows an example of a CSI-RS resource configuration method (normal CP) according to embodiment 2-5 of the present disclosure.

TABLE 17

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. At this time, for example, the symbol a of the 12 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 7 below.

here,

Same as

In the case of the pattern shown in FIG. 29, 0-5 port and 6-11 port are divided and transmitted in each OFDM symbol. The current LTE Rel-10 8Tx codebook and Rel-12 4Tx codebook are designed with the assumption that the first four or two antennas are +45 degrees polarized and the subsequent four or two antennas are -45 degrees polarized. It became. If the codebook to support 12 port CSI-RS is designed using the same principle, beam selection will experience the same phase shift due to time difference when 0-5 port and 6-11 port are transmitted through the same OFDM symbol. While the error can be selected relatively by reflecting only the phase shift difference due to the frequency difference, the phase shift due to the time difference is concentrated in the co-phasing between antennas with different polarizations, and the error can be increased in the corresponding portion. In contrast, when transmitted through OFDM symbols at different times, a phase shift may occur only in OFDM symbols of some ports among antennas having the same polarization, which may cause the same level of error in beam selection and co-phasing determined by the UE. . However, this pattern has the advantage of being able to reflect the error over time in beam selection and co-phasing within a single RB.

FIG. 31 is a view illustrating a port location changed in the pattern shown in FIG. 29 to reflect this effect. In an embodiment 2-5 of the present disclosure, a resource configuration for 12 port CSI-RS based on the pattern illustrated in FIG. 31 may be configured as shown in Table 18 below. Table 18 below shows another example of a CSI-RS resource configuration method (normal CP) according to embodiment 2-5 of the present disclosure.

TABLE 18

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. In this case, for example, the symbol a of the 12 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 8 below.

here,

Same as

Embodiments 2-6 of the present disclosure are methods for supporting twelve CSI-RS ports.

FIG. 32 illustrates 12 CSIs by additionally using REs used as PDSCHs as well as existing CSI-RS REs to support 12 CSI-RS ports in a mobile communication system according to embodiments 2-6 of the present disclosure. -RS port is shown to be supported.

As described above, a total of 40 CSI-RS REs of one PRB are included. Therefore, when 72 REs are used as CSI-RS REs to make the total number of CSI-RS REs in multiples of 12, Six 12 port CSI-RSs can be used in one RB. Embodiment 2-6 of the present disclosure additionally uses 24 PDSCH REs of

OFDM symbols

2 and 3 of all RBs as shown by reference numeral 3220 of FIG. 32, and uses

OFDM symbols

5 and 6 as shown by reference numeral 3210. Six 12-port CSI-RSs are generated by including 8 REs in addition to 16 REs used in

OFDM symbols

12 and 13. When using the second to sixth embodiments of the present disclosure, all reference signals of CSI-RS configuration may use the same structure. Since all six CSI-RS ports exist in the same time resource, power boosting of up to 4.8 dB (3 times) is possible, which can improve channel estimation performance through reference signals. In addition, when using the second embodiment 6-6 of the present disclosure, since the number of configurable settings in a maximum of one PRB is six, several cells and terminals are located at each other's CSI-RS location more than when using conventional CSI-RS REs. Multiplexing can be avoided by avoiding mutual interference in terms of damage time and frequency. However, as described above, existing UEs must puncturing PDSCHs of corresponding REs. In addition, the existing UEs are decoded by considering the CSI-RS as a PDSCH because there is no means for receiving information on such puncturing, and thus the CSI-RS of the corresponding RE acts as interference to the existing UEs. .

As in the case of the second to fifth embodiments of the present disclosure, the CSI-RS pattern of the second to sixth embodiments of the present disclosure uses the second OFDM symbol that can be used as the PDCCH symbol. The PDCCH contains control-related information that is very important to the UE and cannot be solved by simply puncturing the information. Therefore, in this case, the total number of PDCCH symbols should be limited to two existing terminals and new terminals, and it should be informed that two PDCCH symbols are provided through the PCFICH. However, even though the number of PCFICH symbols is three, if the CSI-RS is configured in the corresponding subframe can be solved through the following methods.

Method 1: Ignore the CSI-RS setting and follow PCFICH.

Second method: determine that the PCFICH is set incorrectly, and measure the channel through the CSI-RS.

In the first method, when the number of PDCCH OFDM symbols indicated by the PCFICH is 3, all of the CSI-RSs set in the corresponding subframe are ignored. In this case, when the CSI-RS pattern of FIG. 32 is used, a portion overlapping with a PDCCH symbol appears in all CSI-RS configurations, resulting in the use of 12 port CSI-RS in the corresponding subframe. Therefore, in the second to sixth embodiments of the present disclosure, in order to consider the CSI-RS pattern based on the first method, the pattern shown in FIG. 33 may be used.

FIG. 33 shows a CSI-RS pattern designed based on the first method in embodiments 2-6 of the present disclosure.

In the case of the pattern shown in FIG. 33, there are two settings located in symbol 2 that can be used as a PDCCH, and the remaining settings can be used as CSI-RS. In addition, in the case of the pattern shown in FIG. 33, since all CSI-RS ports are transmitted in the same OFDM symbol, a power boosting value of up to 7.8 dB (6 times) is available, which is compared with the pattern shown in FIG. The advantage is that more power boosting is available if the hardware can support it.

In a second embodiment of the present disclosure, a resource configuration for 12 port CSI-RS considering the pattern of FIG. 32 may be configured as shown in Table 19 below. Table 19 below shows an example of a CSI-RS resource configuration method (normal CP) according to embodiment 2-6 of the present disclosure.

TABLE 19

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. At this time, for example, the symbol a of the 12 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 9 below.

here,

Same as

In the case of the pattern shown in FIG. 32, 0-5 port and 6-11 port are divided and transmitted in each OFDM symbol. Currently, the Rel-10 8Tx codebook and Rel-12 4Tx codebook of LTE are designed with the assumption that the first four or two antennas are +45 degrees polarized and the next four or two antennas are -45 degrees polarized. If the codebook for 12 port CSI-RS is designed using the same principle as this conventional codebook, beam selection is the same phase by time difference when 0-5 port and 6-11 port are transmitted through the same OFDM symbol. Relatively small error can be selected by reflecting only the phase shift difference due to the frequency difference, whereas the phase shift due to time difference is concentrated in the co-phasing between antennas with different polarizations, and the error can be increased in the corresponding part. . In contrast, when transmitted through OFDM symbols at different times, a phase shift may occur only in OFDM symbols of some ports among antennas having the same polarization, which may cause the same level of error in beam selection and co-phasing determined by the UE. . However, this pattern has the advantage of being able to reflect the error over time in beam selection and co-phasing within a single RB.

FIG. 34 is a view illustrating a port location changed in the pattern shown in FIG. 33 to reflect this effect. In a second embodiment of the present disclosure, the resource configuration for the 12 port CSI-RS based on the pattern shown in FIG. 34 may be configured as shown in Table 20 below. Table 20 below shows another example of a CSI-RS resource configuration method (normal CP) according to embodiment 2-6 of the present disclosure.

TABLE 20

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. At this time, for example, the symbol a of the 12 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 10 below.

here,

Same as

Embodiments 2-7 of the present disclosure are methods for supporting 16 CSI-RS ports.

FIG. 35 illustrates 16 CSIs by additionally using REs used as PDSCHs as well as existing CSI-RS REs to support 16 CSI-RS ports in a mobile communication system according to embodiments 2-7 of the present disclosure. -RS port is shown to be supported.

As described above, a total of 40 CSI-RS REs of one PRB are included. Therefore, when 24 REs are used as CSI-RS REs to make the total number of CSI-RS REs in multiples of 16, four 16 port CSI-RSs may be used in one RB. Embodiment 2-7 of the present disclosure is to generate four 16-port CSI-RS by additionally using 24 PDSCH REs of OFDM symbols # 2 and # 3 of all RBs as shown by reference numeral 3510 of FIG. In case of using the embodiment 2-7 of the present disclosure, all CSI-RS configuration reference signals may use the same structure, and eight CSI-RS ports exist in the same time resource, enabling power boosting of up to 6 dB. This can improve the channel estimation performance through the reference signal. In addition, in the case of using the second to seventh embodiments of the present disclosure, since the number of configurations that can be configured in a maximum of one PRB is four, several cells and terminals are located at different CSI-RS locations than when using conventional CSI-RS REs. Multiplexing can be avoided by avoiding mutual interference in terms of damage time and frequency. However, as described above, existing UEs must puncturing PDSCHs of corresponding REs. In addition, the existing UEs are decoded by considering the CSI-RS as a PDSCH because there is no means for receiving information on such puncturing, and thus the CSI-RS of the corresponding RE acts as interference to the existing UEs. .

Like the above-described embodiments 2-5 and 2-6 of the present disclosure, the CSI-RS pattern shown in FIG. 35 also uses the second OFDM symbol that can be used as the PDCCH symbol. The PDCCH contains control-related information that is very important to the UE and cannot be solved by simply puncturing the information. Therefore, in this case, the total number of PDCCH symbols should be limited to two existing terminals and new terminals, and it should be informed that two PDCCH symbols are provided through the PCFICH. However, even though the number of PCFICH symbols is three, if the CSI-RS is configured in the corresponding subframe can be solved through the following methods.

Method 1: Ignore the CSI-RS setting and follow PCFICH.

In the first method, when the number of PDCCH OFDM symbols indicated by the PCFICH is 3, the CSI-RS set in the corresponding subframe is ignored. In this case, when the CSI-RS pattern of FIG. 35 is used, a portion overlapping with a PDCCH symbol appears in all CSI-RS configurations, resulting in the inability to use 16 port CSI-RS in the corresponding subframe. Accordingly, in order to consider the CSI-RS pattern based on the first method in the second to seventh embodiments of the present disclosure, the pattern shown in FIG. 36 may be used.

36 illustrates a CSI-RS pattern designed based on the first method in embodiments 2-7 of the present disclosure.

In the case of the pattern shown in FIG. 36, there are two settings located in symbol 2 that can be used as the PDCCH, and the remaining settings can be used as the CSI-RS. In addition, in the case of the pattern shown in FIG. 36, since all CSI-RS ports are transmitted in the same OFDM symbol, when the hardware supports the power boosting value of 9 dB (6 times), the pattern shown in FIG. 35 may be used. Compared to this, more power boosting can be used if it can be supported in hardware.

In the second to seventh embodiments of the present disclosure, the resource configuration for the 16 port CSI-RS considering the pattern illustrated in FIG. 35 may be configured as shown in Table 21 below. Table 21 below shows an example of a CSI-RS resource configuration method (normal CP) according to embodiments 2-7 of the present disclosure.

TABLE 21

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. At this time, for example, the symbol a of the 16 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 11 below.

here,

Same as

In the case of the pattern shown in FIG. 35, 0-7 ports and 8-15 ports are divided and transmitted in each OFDM symbol. Currently, the Rel-10 8Tx codebook and Rel-12 4Tx codebook of LTE are designed with the assumption that the first four or two antennas are +45 degrees polarized and the next four or two antennas are -45 degrees polarized. If the codebook for supporting 16 CSI-RS ports is designed under the same principle, beam selection will experience the same phase shift and frequency when the 0-7 and 8-15 ports are transmitted over the same OFDM symbol. While the error can be selected relatively by reflecting only the phase shift due to the difference, the phase shift due to the time difference is concentrated in the co-phasing between the antennas with different polarizations, and the error can be increased in the corresponding part. In contrast, when transmitted through OFDM symbols at different times, a phase shift may occur only in OFDM symbols of some ports among antennas having the same polarization, which may cause the same level of error in beam selection and co-phasing determined by the UE. . However, this pattern has the advantage of being able to reflect the error over time in beam selection and co-phasing within a single RB.

FIG. 37 is a view illustrating modified port positions in the pattern illustrated in FIG. 35 to reflect this effect. In the second to seventh embodiments of the present disclosure, a resource configuration for 16 port CSI-RS based on the pattern shown in FIG. 37 may be configured as shown in Table 22 below. Table 22 below shows another example of a CSI-RS resource configuration method (normal CP) according to embodiments 2-7 of the present disclosure.

TABLE 22

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. At this time, for example, the symbol a of the 16 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 12 below.

here,

Same as

Embodiments 2-8 of the present disclosure are methods for supporting 32 CSI-RS ports.

FIG. 38 is a diagram illustrating 32 CSI using additional REs used as PDSCH as well as existing CSI-RS REs to support 32 CSI-RS ports in a mobile communication system according to embodiments 2-8 of the present disclosure. -RS port is shown to be supported.

As described above, a total of 40 CSI-RS REs of one PRB are included. Therefore, when 64 REs are used as CSI-RS REs to make the total number of CSI-RS REs in multiples of 32, Two 32 port CSI-RSs can be used in one RB. Embodiment 2-8 of the present disclosure is to generate two 32-port CSI-RSs by additionally using 24 PDSCH REs of

OFDM symbols

2 and 3 of all RBs as shown by reference numeral 3810 of FIG. 38. 2-8 of the present disclosure In the case of using the embodiment, it is impossible for the 32 CSI-RSs to use the same structure for the reference signals of all CSI-RS configuration in consideration of the existing CSI-RS REs and the DM-RS structure. In the case of using the embodiment 2-8 of the present disclosure, all 16 CSI-RS ports exist in the same time resource, enabling power boosting of up to 12 dB (8 times) to improve channel estimation performance through a reference signal. You can. In addition, in the case of using the embodiment 2-8 of the present disclosure, since the number of configurations that can be configured in a maximum of one PRB is two, multiple cells and terminals than multiplexing in one PRB using existing CSI-RS REs are not possible. They can avoid multiple CSI-RS locations and avoid multiplexing each other in time and frequency dimensions. However, as described above, existing UEs must puncturing PDSCHs of corresponding REs. In addition, the existing UEs are decoded by considering the CSI-RS as a PDSCH because there is no means for receiving information on such puncturing, and thus the CSI-RS of the corresponding RE acts as interference to the existing UEs. .

As described in the above embodiments, the CSI-RS pattern shown in FIG. 38 according to the second to eighth embodiments of the present disclosure also uses the second OFDM symbol that can be used as the PDCCH symbol. The PDCCH contains control-related information that is very important to the UE and cannot be solved by simply puncturing the information. Therefore, in this case, the total number of PDCCH symbols should be limited to two existing terminals and new terminals, and it should be informed that two PDCCH symbols are provided through the PCFICH. However, even though the number of PCFICH symbols is three, if the CSI-RS is configured in the corresponding subframe can be solved through the following methods.

Method 1: Ignore the CSI-RS setting and follow PCFICH.

In the first method, when the number of PDCCH OFDM symbols indicated by the PCFICH is 3, all of the CSI-RSs set in the corresponding subframe are ignored. In this case, when the CSI-RS pattern shown in FIG. 38 is used, a portion overlapping with the PDCCH symbol appears in all CSI-RS configurations, resulting in the use of 32 port CSI-RS in the corresponding subframe. Accordingly, in order to consider the CSI-RS pattern based on the first method in the second to eighth embodiments of the present disclosure, the pattern shown in FIG. 39 may be used.

39 shows a CSI-RS pattern designed based on the first method in embodiments 2-8 of the present disclosure.

In the case of the pattern shown in FIG. 39, there is one configuration located in symbol 2 that can be used as a PDCCH, and the other configuration can be used as a CSI-RS. Further, in the case of the pattern shown in FIG. 39, since many CSI-RS ports are transmitted in

OFDM symbols

2, 3, 9, and 10, a large power can be boosted in the case of the CSI-RS port located in the symbol. However, the ports of

symbols

5, 6 and 12, 13 are limited to 6dB maximum.

In the second method, when the 32-port CSI-RS configured in the corresponding subframe exists in the PDCCH OFDM symbol region, it is determined that the PCFICH is transmitted incorrectly, and the PCFICH is assumed to be 2 and used. In the case of the second method, the channel is not measured in the configured CSI-RS port. However, when the actual PDCCH uses three OFDM symbols and the CSI-RS port is not transmitted, the operation may not be performed properly.

In an embodiment 2-8 of the present disclosure, a resource configuration for 32 port CSI-RS based on the pattern illustrated in FIG. 38 may be configured as shown in Table 23 below. Table 23 below shows an example of a CSI-RS resource configuration method (normal CP) according to embodiments 2-8 of the present disclosure.

TABLE 23

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. At this time, for example, the symbol a of the 12 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 13 below.

here,

Same as

40 illustrates CSI-RS patterns for 32 port configured based on Embodiments 2-8 of the present disclosure. Resource configuration and 32 port CSI-RS symbol illustrated in Embodiments 2-8 of the present disclosure. A similar definition can be used.

Embodiments 2-9 of the present disclosure are methods for supporting 16 CSI-RS ports.

FIG. 41 illustrates a configuration in which 16 CSI-RS ports are supported in a PRB and two PRBs combined to support 16 CSI-RS ports in a mobile communication system according to embodiments 2-9 of the present disclosure. It is shown that all of the configurations that support -RS port are supported at once.

As described above, a total of 40 CSI-RS REs of one PRB are included. Embodiments 2-9 of the present disclosure presently support 16 CSI-RS ports in 40 CSI-RS REs according to CSI-RS port configuration. The port is supported, and in another specific configuration, 16 CSI-RS ports can be measured through two PRBs. In this case, in addition to securing two CSI-RS port configuration in one RB, one additional CSI-RS port configuration can be secured through two RBs. Therefore, the number of cases where multiplexing is possible in time and frequency configuration rather than discarding 8 REs for 16 port CSI-RS support is increased. In addition, the density of the reference signal is always fixed to 1 RE / RB / port in the conventional CSI-RS, but the difference is that 0.5 RE / RB / port can be used by using the CSI-RS port configuration. When the density of the reference signal is reduced in this way, the accuracy of channel estimation may be lowered, but the overhead of using the reference signal may be reduced.

In the case of the existing 4 and 8 port CSI-RS, the CSI-RS ports under the same configuration are transmitted using the same time resources in order to maximize the performance of estimating the radio channel through the reference signal. Accordingly, a 3dB power gain can be achieved in the case of 4 port CSI-RS and a 6dB power boosting effect can be achieved in the case of 8 port CSI-RS. However, in the case of the CSI-RS pattern illustrated in FIG. 35, a power boosting effect of 6 dB may be obtained at setting 0, and a power boosting effect of 9 dB may be obtained at setting 1 and setting 2. Therefore, setting 1 gets all RB and maximum power boosting effects, and setting 0 and 2 are designed to divide the damage in power boosting or ports per RB respectively.

Resource configuration for the 16 port CSI-RS based on the pattern shown in FIG. 41 according to the embodiment 2-9 of the present disclosure may be configured as shown in Table 24 below. Table 24 below shows an example of a CSI-RS resource configuration method (normal CP) according to embodiment 2-9 of the present disclosure.

TABLE 24

Where p is the port index, and the port of the 0th antenna is represented by 15. When the antenna index increases, the port index also increases. At this time, for example, the symbol a of the 16 port CSI-RS transmitted in the k-th frequency RE and the l-th time symbol may be defined as in Equation 14 below.

here,

Same as

In the case of setting 0 of the pattern illustrated in FIG. 41 according to an embodiment 2-9 of the present disclosure, 0-7 ports and 8-15 ports are divided and transmitted in each OFDM symbol. Currently, the Rel-10 8Tx codebook and Rel-12 4Tx codebook of LTE are designed with the assumption that the first four or two antennas are +45 degrees polarized and the next four or two antennas are -45 degrees polarized. If the codebook for supporting 16 CSI-RS ports is designed under the same principle, beam selection will experience the same phase shift and frequency when the 0-7 and 8-15 ports are transmitted over the same OFDM symbol. While the error can be selected relatively by reflecting only the phase shift due to the difference, the phase shift due to the time difference is concentrated in the co-phasing between the antennas with different polarizations, and the error can be increased in the corresponding part. In contrast, when transmitted through OFDM symbols at different times, phase shifts may occur only in OFDM symbols of some ports among antennas having the same polarization, which may cause the same level of error in beam selection and co-phasing determined by the UE. . However, this pattern has the advantage of being able to reflect the error over time in beam selection and co-phasing in a single PRB. FIG. 42 is a diagram illustrating port locations of the pattern shown in FIG. 41 in order to reflect this effect in embodiments 2-9 of the present disclosure.

In the above, the CSI-RS pattern configuration of the CSI-RS pattern according to the second embodiment of the present disclosure has been described with reference to FIGS. 20 through 42, and the second embodiment of the present disclosure is described below with reference to FIGS. 43 to 46. A method and apparatus for measuring a channel according to the present invention will be described.

43 illustrates a method of measuring a channel in a terminal according to a second embodiment of the present disclosure.

Referring to FIG. 43, a terminal receives configuration information about a CSI-RS configuration according to a second embodiment of the present disclosure from a base station (4410). Here, the configuration information includes at least one of the number of ports for each CSI-RS, the timing and resource location at which each CSI-RS is transmitted, and the transmission power information.

In operation 4320, the terminal receives one feedback configuration information on at least one CSI-RS generated based on the configuration information from the base station.

Then, when the terminal receives the CSI-RS configuration according to the second embodiment of the present disclosure from the base station, a channel between the transmitting antenna of the base station and the receiving antenna of the terminal based on the feedback setting information on the received CSI-RS configuration Estimate (4330).

The terminal generates feedback information rank, PMI, and CQI based on the received feedback configuration information and a predefined codebook based on the virtual channel added between the estimated channel and the CSI-RS (4340). ). Thereafter, the terminal transmits the generated feedback information to the base station (2250) at the feedback timing included in the received feedback configuration information, and ends the channel feedback generation and reporting process considering the two-dimensional arrangement. 44 illustrates a method of measuring a channel in a base station according to the second embodiment of the present disclosure.

Referring to FIG. 44, according to a second embodiment of the present disclosure, a base station transmits configuration information on a CSI-RS for measuring a channel to a terminal (4410). The configuration information includes at least one of the number of ports for each CSI-RS, timing and resource location at which each CSI-RS is transmitted, and transmission power information.

In operation 4420, the base station transmits feedback configuration information on at least one CSI-RS to the terminal based on the configuration information. Thereafter, the base station transmits the CSI-RS configuration according to the second embodiment of the present disclosure to the terminal and receives the feedback information from the terminal at a predetermined timing (4430). In this case, the terminal estimates a channel for each antenna port and estimates an additional channel for the virtual resource based on the channel. The terminal generates feedback information based on the feedback setting information received from the base station and a predefined codebook and transmits the feedback information to the base station. Accordingly, the base station receives feedback information from the terminal at a predetermined timing, and is used to determine the channel state between the terminal and the base station.

45 briefly illustrates an internal configuration of a terminal for measuring a channel according to the second embodiment of the present disclosure.

Referring to FIG. 45, the terminal 4500 includes a communication unit 4510 and a controller 4520.

The communication unit 4510 performs a function of transmitting or receiving a signal from the outside (for example, a base station). Herein, the communication unit 4510 may receive feedback setting information from the base station under the control of the controller 4520, and transmit the feedback information to the base station.

The controller 4520 controls the states and operations of all components constituting the terminal 4500. In more detail, the controller 4520 generates feedback information based on the feedback setting information received from the base station. In addition, the controller 2420 controls the communicator 4510 to feed back the generated feedback information to the base station according to the timing information included in the feedback setting information received from the base station. The controller 4520 may include a channel estimator 4530.

The channel estimator 4530 determines necessary feedback information through the CSI-RS and feedback configuration information received from the base station, and estimates a channel using the received CSI-RS based on the feedback information.

In FIG. 45, an example in which the terminal 4500 includes the communication unit 4510 and the controller 4520 is described. However, the present disclosure is not limited thereto and may further include various components according to a function performed by the terminal 4500. For example, the terminal 4500 may further include a display unit displaying a current state of the terminal 4500, an input unit to which a signal such as a function is performed from a user, a storage unit storing data generated in the terminal 4500, and the like. Can be. In addition, although the channel estimator 4530 is included in the controller 4520, the present invention is not limited thereto. The controller 4520 may control the communicator 4510 to receive configuration information about each of at least one reference signal resource from the base station. The controller 4520 may control the communicator 4510 to measure the at least one reference signal and to receive feedback setting information for generating feedback information according to the measurement result from the base station. In addition, the controller 4520 may measure at least one reference signal received through the communication unit 4510 and generate feedback information according to the feedback setting information. The controller 4520 may control the communicator 4510 to transmit the generated feedback information to the base station at a feedback timing according to the feedback setting information. In addition, the controller 4520 may receive the CSI-RS from the base station, generate feedback information based on the received CSI-RS, and transmit the generated feedback information to the base station. At this time, the controller 4520 may select a precoding matrix for each antenna port group of the base station and further select one additional precoding matrix based on the relationship between the antenna port groups of the base station. have.

In addition, the controller 4520 may receive the CSI-RS from the base station, generate feedback information based on the received CSI-RS, and transmit the generated feedback information to the base station. In this case, the controller 4520 may select one precoding matrix for all antenna port groups of the base station. In addition, the controller 4520 receives feedback setting information from a base station, receives a CSI-RS from the base station, generates feedback information based on the received feedback setting information and the received CSI-RS, and generates the generated information. Feedback information may be transmitted to the base station. In this case, the controller 4520 may receive additional feedback setting information based on the relationship between the feedback setting information corresponding to each antenna port group of the base station and the antenna port group.

46 briefly illustrates an internal configuration of a base station for measuring a channel according to the second embodiment of the present disclosure.

Referring to FIG. 46, the base station 4600 includes a control unit 4610 and a communication unit 4620. The controller 4610 controls the states and operations of all components of the base station 4600. In detail, the controller 4610 allocates the CSI-RS resource for channel estimation of the terminal 4500 to the terminal 4500 and allocates the feedback resource and the feedback timing to the terminal 4500. To this end, the controller 4610 may further include a resource allocator 2630. In addition, the feedback setting information including the feedback timing of the base station 4600 is transmitted to the terminal 4500 so that the feedback from various terminals does not collide, and the feedback information set at the corresponding feedback timing is received and interpreted. The communication unit 4620 performs a function of transmitting and receiving data, a reference signal, and feedback information to the terminal 4500. Herein, the communication unit 4620 transmits the CSI-RS to the terminal 4500 through the allocated resources under the control of the controller 4610, and receives feedback information on the channel information from the terminal 4500.

Although the resource allocator 4630 is included in the controller 4610, the resource allocator 4630 is not limited thereto. The controller 4610 may control the communicator 4620 to transmit setting information about each of at least one reference signal to the terminal 4500, or may generate the at least one reference signal. In addition, the controller 4610 may control the communication unit 4620 to transmit the feedback setting information for generating the feedback information according to the measurement result to the terminal 4500. In addition, the controller 4610 transmits the at least one reference signal to the terminal 4500, and receives the feedback information transmitted from the terminal 4500 at a feedback timing according to the feedback setting information. Can be controlled. In addition, the controller 4610 transmits feedback setting information to the terminal 4500, transmits a CSI-RS to the terminal 4500, and outputs feedback information generated based on the feedback setting information and the CSI-RS. It can receive from the terminal 4500. In this case, the controller 4610 may transmit additional feedback setting information based on the relationship between the feedback setting information corresponding to each antenna port group of the base station 4600 and the antenna port group. In addition, the controller 4610 may transmit the beamformed CSI-RS to the terminal 4500 based on the feedback information, and receive feedback information generated based on the CSI-RS from the terminal 4500. . According to the second embodiment of the present disclosure described above, an excessive feedback resource is allocated for transmitting CSI-RS in a base station having a large number of two-dimensional antenna array structure transmitting antennas and an increase of channel estimation complexity of the terminal 4500. In this case, the terminal 4500 may effectively measure all channels for a large number of transmit antennas and configure this as feedback information to notify the base station 4600.

Meanwhile, in the detailed description of the present disclosure, specific embodiments have been described. However, various modifications may be possible without departing from the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined not only by the appended claims, but also by the equivalents of the claims.

Claims

In the method for measuring a channel in a mobile communication system,

Receiving, from the base station, configuration information for channel measurement using a reference signal;

Receiving the reference signal from the base station;

Measuring a channel using the reference signal based on the configuration information; And

Transmitting the information on the measured channel to the base station,

The configuration information includes at least one of information on the time for the channel measurement and information on the number of ports for the reference signal.
The method of claim 1, wherein the information about the time for measuring the channel comprises at least one of a time point for initializing the measurement for the channel, a time point for measuring the channel, and a time point for transmitting information about the measured channel to the base station. Contains information about one,

The configuration information may further include information on at least one of a location and a transmission power of a resource to which the reference signal is transmitted.
The method of claim 1, wherein the configuration information is triggered periodically or aperiodically for the terminal.
The method of claim 3, wherein

The configuration information is received via higher layer signaling, downlink control information (DCI) for uplink data scheduling, and transmit power control (TPC) DCI method.
The method of claim 3, wherein

Wherein the setting information is received through one of configuration information for the reference signal, a reference signal process, and a new transmission mode.
The method of claim 1, wherein the setting information,

Method for measuring a channel, characterized in that for supporting the reference signal port of one of 12, 16 and 32 reference signal ports.
A terminal in a mobile communication system,

Transmitting and receiving unit for transmitting and receiving data; And

Receives, from a base station, configuration information for channel measurement using a reference signal, controls the transceiver to receive the reference signal, measures a channel using the reference signal based on the configuration information, and measures the measured information. A control unit controlling the transceiver to transmit information about a channel to the base station,

The configuration information terminal comprises at least one of information on the time for the channel measurement and information on the number of ports for the reference signal.
A terminal of claim 7 adapted to operate according to any of the methods of claims 2 to 6.
In the method for measuring a channel in a mobile communication system,

Transmitting setting information for channel measurement to the terminal using a reference signal;

Transmitting the reference signal to the terminal; And

Receiving information about a channel measured by using the reference signal based on the configuration information from the terminal,

The configuration information includes at least one of information on the time for the channel measurement and information on the number of ports for the reference signal.
The method of claim 9, wherein the information about the time for measuring the channel comprises at least one of a time point for initializing a measurement for the channel, a time point for measuring the channel, and a time point for transmitting information about the measured channel to the base station. Contains information about one,

The configuration information may further include information on at least one of a location and a transmission power of a resource to which the reference signal is transmitted.
10. The method of claim 9, wherein the configuration information is triggered periodically or aperiodically for the terminal.
The method of claim 11,

The configuration information is received through higher layer signaling, downlink control information (DCI) for uplink data scheduling, transmit power control (TPC) DCI, or configuration information on the reference signal. And receiving via one of a reference signal process and a new transmission mode.
The method of claim 9, wherein the setting information,

Method for measuring a channel, characterized in that for supporting the reference signal port of one of 12, 16 and 32 reference signal ports.
A base station in a mobile communication system,

Transmitting and receiving unit for transmitting and receiving data; And

Transmitting configuration information for channel measurement to a terminal using a reference signal, transmitting the reference signal to the terminal, and receiving information on the channel measured using the reference signal based on the configuration information from the terminal. It includes a control unit for controlling the transmission and reception unit,

The configuration information base station, characterized in that at least one of the information about the time for the channel measurement and the information on the number of ports for the reference signal.
The base station of claim 14 adapted to operate according to any of the methods of claims 9-13.